feat(config): Make all configuration overridable (#4575)

.github/workflows/cargo.yml

@@ -93,10 +93,14 @@ jobs:
             os: ubuntu-latest
           - crate: better_scoped_tls
             os: ubuntu-latest
+          - crate: binding_commons
+            os: ubuntu-latest
           - crate: binding_core_node
             os: ubuntu-latest
           - crate: binding_core_wasm
             os: ubuntu-latest
+          - crate: binding_css_node
+            os: ubuntu-latest
           - crate: enum_kind
             os: ubuntu-latest
           - crate: from_variant
@@ -136,6 +140,10 @@ jobs:
               cargo hack check --feature-powerset --no-dev-deps
           - crate: swc_common
             os: windows-latest
+          - crate: swc_config
+            os: ubuntu-latest
+          - crate: swc_config_macro
+            os: ubuntu-latest
           - crate: swc_css
             os: ubuntu-latest
           - crate: swc_css_ast

Cargo.lock

@@ -60,9 +60,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.56"
+version = "1.0.57"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4361135be9122e0870de935d7c439aef945b9f9ddd4199a553b5270b49c82a27"
+checksum = "08f9b8508dccb7687a1d6c4ce66b2b0ecef467c94667de27d8d7fe1f8d2a9cdc"
 
 [[package]]
 name = "arbitrary"
@@ -2553,9 +2553,9 @@ checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
 [[package]]
 name = "serde"
-version = "1.0.136"
+version = "1.0.137"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ce31e24b01e1e524df96f1c2fdd054405f8d7376249a5110886fb4b658484789"
+checksum = "61ea8d54c77f8315140a05f4c7237403bf38b72704d031543aa1d16abbf517d1"
 dependencies = [
  "serde_derive",
 ]
@@ -2593,9 +2593,9 @@ dependencies = [
 
 [[package]]
 name = "serde_derive"
-version = "1.0.136"
+version = "1.0.137"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08597e7152fcd306f41838ed3e37be9eaeed2b61c42e2117266a554fab4662f9"
+checksum = "1f26faba0c3959972377d3b2d306ee9f71faee9714294e41bb777f83f88578be"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2892,12 +2892,14 @@ dependencies = [
  "pathdiff",
  "rayon",
  "regex",
+ "rustc-hash",
  "serde",
  "serde_json",
  "sourcemap",
  "swc_atoms",
  "swc_cached",
  "swc_common",
+ "swc_config",
  "swc_ecma_ast",
  "swc_ecma_codegen",
  "swc_ecma_ext_transforms",
@@ -3051,6 +3053,28 @@ dependencies = [
  "url",
 ]
 
+[[package]]
+name = "swc_config"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+ "indexmap",
+ "serde",
+ "serde_json",
+ "swc_config_macro",
+]
+
+[[package]]
+name = "swc_config_macro"
+version = "0.1.0"
+dependencies = [
+ "pmutil",
+ "proc-macro2",
+ "quote",
+ "swc_macros_common",
+ "syn",
+]
+
 [[package]]
 name = "swc_css"
 version = "0.104.2"
@@ -3271,6 +3295,7 @@ dependencies = [
  "serde",
  "swc_atoms",
  "swc_common",
+ "swc_config",
  "swc_ecma_ast",
  "swc_ecma_codegen",
  "swc_ecma_parser",
@@ -3324,6 +3349,7 @@ dependencies = [
  "swc_atoms",
  "swc_cached",
  "swc_common",
+ "swc_config",
  "swc_ecma_ast",
  "swc_ecma_codegen",
  "swc_ecma_parser",
@@ -3555,6 +3581,7 @@ dependencies = [
  "indexmap",
  "once_cell",
  "rayon",
+ "rustc-hash",
  "serde_json",
  "swc_atoms",
  "swc_common",
@@ -3878,7 +3905,7 @@ dependencies = [
 
 [[package]]
 name = "swc_macros_common"
-version = "0.3.4"
+version = "0.3.5"
 dependencies = [
  "pmutil",
  "proc-macro2",
@@ -4053,9 +4080,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.86"
+version = "1.0.92"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8a65b3f4ffa0092e9887669db0eae07941f023991ab58ea44da8fe8e2d511c6b"
+checksum = "7ff7c592601f11445996a06f8ad0c27f094a58857c2f89e97974ab9235b92c52"
 dependencies = [
  "proc-macro2",
  "quote",

crates/binding_commons/Cargo.toml

@@ -19,7 +19,7 @@ napi = { version = "2", default-features = false, features = [
   "serde-json",
 ] }
 serde = { version = "1", features = ["derive"] }
-serde_json = "1"
+serde_json = { version = "1", features = ["unbounded_depth"] }
 swc_node_base = { path = "../swc_node_base" }
 tracing = { version = "0.1.32", features = ["release_max_level_info"] }
 tracing-subscriber = { version = "0.3.9", features = ["env-filter"] }

crates/binding_core_node/src/bundle.rs

@@ -115,7 +115,7 @@ impl Task for BundleTask {
                             .config
                             .options
                             .as_ref()
-                            .map(|v| v.config.minify)
+                            .map(|v| v.config.minify.into_bool())
                             .unwrap_or(false);
 
                         let output = self.swc.print(

crates/binding_core_node/src/print.rs

@@ -43,7 +43,7 @@ impl Task for PrintTask {
                     .unwrap_or(SourceMapsConfig::Bool(false)),
                 &Default::default(),
                 None,
-                options.config.minify,
+                options.config.minify.into_bool(),
                 None,
             )
             .convert_err()
@@ -100,7 +100,7 @@ pub fn print_sync(program: String, options: Buffer) -> napi::Result<TransformOut
             .unwrap_or(SourceMapsConfig::Bool(false)),
         &Default::default(),
         None,
-        options.config.minify,
+        options.config.minify.into_bool(),
         None,
     )
     .convert_err()

crates/binding_core_node/src/transform.rs

@@ -48,7 +48,7 @@ impl Task for TransformTask {
 
         try_with(
             self.c.cm.clone(),
-            !options.config.error.filename,
+            !options.config.error.filename.into_bool(),
             |handler| {
                 self.c.run(|| match &self.input {
                     Input::Program(ref s) => {
@@ -130,25 +130,29 @@ pub fn transform_sync(s: String, is_module: bool, opts: Buffer) -> napi::Result<
         options.config.adjust(Path::new(&options.filename));
     }
 
-    try_with(c.cm.clone(), !options.config.error.filename, |handler| {
+    try_with(
-        c.run(|| {
+        c.cm.clone(),
-            if is_module {
+        !options.config.error.filename.into_bool(),
-                let program: Program =
+        |handler| {
-                    deserialize_json(s.as_str()).context("failed to deserialize Program")?;
+            c.run(|| {
-                c.process_js(handler, program, &options)
+                if is_module {
-            } else {
+                    let program: Program =
-                let fm = c.cm.new_source_file(
+                        deserialize_json(s.as_str()).context("failed to deserialize Program")?;
-                    if options.filename.is_empty() {
+                    c.process_js(handler, program, &options)
-                        FileName::Anon
+                } else {
-                    } else {
+                    let fm = c.cm.new_source_file(
-                        FileName::Real(options.filename.clone().into())
+                        if options.filename.is_empty() {
-                    },
+                            FileName::Anon
-                    s,
+                        } else {
-                );
+                            FileName::Real(options.filename.clone().into())
-                c.process_js_file(fm, handler, &options)
+                        },
-            }
+                        s,
-        })
+                    );
-    })
+                    c.process_js_file(fm, handler, &options)
+                }
+            })
+        },
+    )
     .convert_err()
 }
 
@@ -189,17 +193,21 @@ pub fn transform_file_sync(
         options.config.adjust(Path::new(&options.filename));
     }
 
-    try_with(c.cm.clone(), !options.config.error.filename, |handler| {
+    try_with(
-        c.run(|| {
+        c.cm.clone(),
-            if is_module {
+        !options.config.error.filename.into_bool(),
-                let program: Program =
+        |handler| {
-                    deserialize_json(s.as_str()).context("failed to deserialize Program")?;
+            c.run(|| {
-                c.process_js(handler, program, &options)
+                if is_module {
-            } else {
+                    let program: Program =
-                let fm = c.cm.load_file(Path::new(&s)).expect("failed to load file");
+                        deserialize_json(s.as_str()).context("failed to deserialize Program")?;
-                c.process_js_file(fm, handler, &options)
+                    c.process_js(handler, program, &options)
-            }
+                } else {
-        })
+                    let fm = c.cm.load_file(Path::new(&s)).expect("failed to load file");
-    })
+                    c.process_js_file(fm, handler, &options)
+                }
+            })
+        },
+    )
     .convert_err()
 }

crates/binding_core_wasm/src/lib.rs

@@ -114,7 +114,7 @@ pub fn print_sync(s: JsValue, opts: JsValue) -> Result<JsValue, JsValue> {
                             .unwrap_or(SourceMapsConfig::Bool(false)),
                         &Default::default(),
                         None,
-                        opts.config.minify,
+                        opts.config.minify.into(),
                         None,
                     )
                     .context("failed to print code")?;

crates/binding_css_node/Cargo.toml

@@ -30,7 +30,7 @@ napi-derive = { version = "2", default-features = false, features = [
 node_macro_deps = { path = "../node_macro_deps" }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
-swc_common = { path = "../swc_common", features = ["perf"] }
+swc_common = { path = "../swc_common", features = ["perf", "sourcemap"] }
 swc_css_ast = { path = "../swc_css_ast" }
 swc_css_codegen = { path = "../swc_css_codegen" }
 swc_css_minifier = { path = "../swc_css_minifier" }

crates/swc/Cargo.toml

@@ -30,56 +30,58 @@ anyhow = "1"
 base64 = "0.13.0"
 dashmap = "5.1.0"
 either = "1"
-indexmap = {version = "1", features = ["serde"]}
+indexmap = { version = "1", features = ["serde"] }
 json_comments = "0.2.0"
 lru = "0.7.1"
 once_cell = "1.10.0"
 parking_lot = "0.12.0"
 pathdiff = "0.2.0"
 regex = "1"
-serde = {version = "1", features = ["derive"]}
+serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 sourcemap = "6"
-swc_atoms = {version = "0.2", path = "../swc_atoms"}
+swc_atoms = { version = "0.2", path = "../swc_atoms" }
-swc_cached = {version = "0.1.0", path = "../swc_cached"}
+swc_cached = { version = "0.1.0", path = "../swc_cached" }
-swc_common = {version = "0.17.23", path = "../swc_common", features = [
+swc_common = { version = "0.17.23", path = "../swc_common", features = [
   "sourcemap",
   "concurrent",
   "parking_lot",
-]}
+] }
-swc_ecma_ast = {version = "0.77.0", path = "../swc_ecma_ast"}
+swc_config = { version = "0.1.0", path = "../swc_config" }
-swc_ecma_codegen = {version = "0.106.0", path = "../swc_ecma_codegen"}
+swc_ecma_ast = { version = "0.77.0", path = "../swc_ecma_ast" }
-swc_ecma_ext_transforms = {version = "0.69.0", path = "../swc_ecma_ext_transforms"}
+swc_ecma_codegen = { version = "0.106.0", path = "../swc_ecma_codegen" }
-swc_ecma_lints = {version = "0.38.0", path = "../swc_ecma_lints"}
+swc_ecma_ext_transforms = { version = "0.69.0", path = "../swc_ecma_ext_transforms" }
-swc_ecma_loader = {version = "0.29.0", path = "../swc_ecma_loader", features = [
+swc_ecma_lints = { version = "0.38.0", path = "../swc_ecma_lints" }
+swc_ecma_loader = { version = "0.29.0", path = "../swc_ecma_loader", features = [
   "cache",
   "node",
   "tsc",
-]}
+] }
-swc_ecma_minifier = {version = "0.110.0", path = "../swc_ecma_minifier"}
+swc_ecma_minifier = { version = "0.110.0", path = "../swc_ecma_minifier" }
-swc_ecma_parser = {version = "0.103.0", path = "../swc_ecma_parser"}
+swc_ecma_parser = { version = "0.103.0", path = "../swc_ecma_parser" }
-swc_ecma_preset_env = {version = "0.125.0", path = "../swc_ecma_preset_env"}
+swc_ecma_preset_env = { version = "0.125.0", path = "../swc_ecma_preset_env" }
-swc_ecma_transforms = {version = "0.150.0", path = "../swc_ecma_transforms", features = [
+swc_ecma_transforms = { version = "0.150.0", path = "../swc_ecma_transforms", features = [
   "compat",
   "module",
   "optimization",
   "proposal",
   "react",
   "typescript",
-]}
+] }
-swc_ecma_transforms_base = {version = "0.82.0", path = "../swc_ecma_transforms_base"}
+swc_ecma_transforms_base = { version = "0.82.0", path = "../swc_ecma_transforms_base" }
-swc_ecma_transforms_compat = {version = "0.96.0", path = "../swc_ecma_transforms_compat"}
+swc_ecma_transforms_compat = { version = "0.96.0", path = "../swc_ecma_transforms_compat" }
-swc_ecma_transforms_optimization = {version = "0.120.0", path = "../swc_ecma_transforms_optimization"}
+swc_ecma_transforms_optimization = { version = "0.120.0", path = "../swc_ecma_transforms_optimization" }
-swc_ecma_utils = {version = "0.83.0", path = "../swc_ecma_utils"}
+swc_ecma_utils = { version = "0.83.0", path = "../swc_ecma_utils" }
-swc_ecma_visit = {version = "0.63.0", path = "../swc_ecma_visit"}
+swc_ecma_visit = { version = "0.63.0", path = "../swc_ecma_visit" }
-swc_ecmascript = {version = "0.153.0", path = "../swc_ecmascript"}
+swc_ecmascript = { version = "0.153.0", path = "../swc_ecmascript" }
-swc_error_reporters = {version = "0.1.2", path = "../swc_error_reporters"}
+swc_error_reporters = { version = "0.1.2", path = "../swc_error_reporters" }
-swc_node_comments = {version = "0.4.0", path = "../swc_node_comments"}
+swc_node_comments = { version = "0.4.0", path = "../swc_node_comments" }
-swc_plugin_proxy = {version = "0.2.1", path = "../swc_plugin_proxy", optional = true}
+swc_plugin_proxy = { version = "0.2.1", path = "../swc_plugin_proxy", optional = true }
-swc_plugin_runner = {version = "0.54.0", path = "../swc_plugin_runner", optional = true, default-features = false}
+swc_plugin_runner = { version = "0.54.0", path = "../swc_plugin_runner", optional = true, default-features = false }
-swc_timer = {version = "0.5.0", path = "../swc_timer"}
+swc_timer = { version = "0.5.0", path = "../swc_timer" }
-swc_visit = {version = "0.3.0", path = "../swc_visit"}
+swc_visit = { version = "0.3.0", path = "../swc_visit" }
 tracing = "0.1.32"
+rustc-hash = "1.1.0"
 
 [dependencies.napi-derive]
 default-features = false
@@ -97,11 +99,11 @@ version = "2.0.0"
 ansi_term = "0.12"
 criterion = "0.3"
 rayon = "1.5.1"
-swc_ecma_lints = {version = "0.38.0", path = "../swc_ecma_lints", features = [
+swc_ecma_lints = { version = "0.38.0", path = "../swc_ecma_lints", features = [
   "non_critical_lints",
-]}
+] }
-swc_node_base = {version = "0.5.0", path = "../swc_node_base"}
+swc_node_base = { version = "0.5.0", path = "../swc_node_base" }
-testing = {version = "0.19.0", path = "../testing"}
+testing = { version = "0.19.0", path = "../testing" }
 walkdir = "2"
 
 [[example]]

crates/swc/benches/minify.rs

@@ -4,7 +4,7 @@ extern crate swc_node_base;
 use std::{path::PathBuf, sync::Arc};
 
 use criterion::{black_box, criterion_group, criterion_main, Bencher, Criterion};
-use swc::{config::JsMinifyOptions, try_with_handler};
+use swc::{config::JsMinifyOptions, try_with_handler, BoolOrDataConfig};
 use swc_common::{FilePathMapping, SourceMap};
 
 fn mk() -> swc::Compiler {
@@ -35,8 +35,8 @@ fn bench_minify(b: &mut Bencher, filename: &str) {
                 fm,
                 handler,
                 &JsMinifyOptions {
-                    compress: true.into(),
+                    compress: BoolOrDataConfig::from_bool(true),
-                    mangle: true.into(),
+                    mangle: BoolOrDataConfig::from_bool(true),
                     format: Default::default(),
                     ecma: Default::default(),
                     keep_classnames: Default::default(),

crates/swc/examples/minify.rs

@@ -1,7 +1,7 @@
 use std::{path::Path, sync::Arc};
 
 use anyhow::Context;
-use swc::{self, config::JsMinifyOptions, try_with_handler, HandlerOpts};
+use swc::{self, config::JsMinifyOptions, try_with_handler, BoolOrDataConfig, HandlerOpts};
 use swc_common::SourceMap;
 
 fn main() {
@@ -23,8 +23,8 @@ fn main() {
                 fm,
                 handler,
                 &JsMinifyOptions {
-                    compress: true.into(),
+                    compress: BoolOrDataConfig::from_bool(true),
-                    mangle: true.into(),
+                    mangle: BoolOrDataConfig::from_bool(true),
                     format: Default::default(),
                     ecma: Default::default(),
                     keep_classnames: Default::default(),

crates/swc/src/builder.rs

@@ -1,7 +1,8 @@
-use std::{cell::RefCell, collections::HashMap, path::PathBuf, rc::Rc, sync::Arc};
+use std::{cell::RefCell, path::PathBuf, rc::Rc, sync::Arc};
 
 use compat::{es2015::regenerator, es2020::export_namespace_from};
 use either::Either;
+use rustc_hash::FxHashMap;
 use swc_atoms::JsWord;
 use swc_common::{
     chain,
@@ -21,9 +22,7 @@ use swc_ecma_transforms::{
 };
 use swc_ecma_visit::{as_folder, noop_visit_mut_type, VisitMut};
 
-use crate::config::{
+use crate::config::{CompiledPaths, GlobalPassOption, JsMinifyOptions, ModuleConfig};
-    util::BoolOrObject, CompiledPaths, GlobalPassOption, JsMinifyOptions, ModuleConfig,
-};
 
 /// Builder is used to create a high performance `Compiler`.
 pub struct PassBuilder<'a, 'b, P: swc_ecma_visit::Fold> {
@@ -124,7 +123,7 @@ impl<'a, 'b, P: swc_ecma_visit::Fold> PassBuilder<'a, 'b, P> {
 
     pub fn const_modules(
         self,
-        globals: HashMap<JsWord, HashMap<JsWord, String>>,
+        globals: FxHashMap<JsWord, FxHashMap<JsWord, String>>,
     ) -> PassBuilder<'a, 'b, impl swc_ecma_visit::Fold> {
         let cm = self.cm.clone();
         self.then(const_modules(cm, globals))
@@ -296,7 +295,7 @@ impl<'a, 'b, P: swc_ecma_visit::Fold> PassBuilder<'a, 'b, P> {
         let is_mangler_enabled = self
             .minify
             .as_ref()
-            .map(|v| matches!(v.mangle, BoolOrObject::Bool(true) | BoolOrObject::Obj(_)))
+            .map(|v| v.mangle.is_obj() || v.mangle.is_true())
             .unwrap_or(false);
 
         let module_scope = Rc::new(RefCell::new(Scope::default()));
@@ -351,17 +350,30 @@ impl VisitMut for MinifierPass {
     fn visit_mut_module(&mut self, m: &mut Module) {
         if let Some(options) = &self.options {
             let opts = MinifyOptions {
-                compress: options.compress.clone().into_obj().map(|mut v| {
+                compress: options
-                    if v.const_to_let.is_none() {
+                    .compress
-                        v.const_to_let = Some(true);
+                    .clone()
-                    }
+                    .unwrap_as_option(|default| match default {
-                    if v.toplevel.is_none() {
+                        Some(true) => Some(Default::default()),
-                        v.toplevel = Some(TerserTopLevelOptions::Bool(true));
+                        _ => None,
-                    }
+                    })
+                    .map(|mut v| {
+                        if v.const_to_let.is_none() {
+                            v.const_to_let = Some(true);
+                        }
+                        if v.toplevel.is_none() {
+                            v.toplevel = Some(TerserTopLevelOptions::Bool(true));
+                        }
 
-                    v.into_config(self.cm.clone())
+                        v.into_config(self.cm.clone())
-                }),
+                    }),
-                mangle: options.mangle.clone().into_obj(),
+                mangle: options
+                    .mangle
+                    .clone()
+                    .unwrap_as_option(|default| match default {
+                        Some(true) => Some(Default::default()),
+                        _ => None,
+                    }),
                 ..Default::default()
             };
 

crates/swc/src/config/mod.rs

@@ -3,7 +3,6 @@ use std::{
     cell::RefCell,
     collections::{HashMap, HashSet},
     env, fmt,
-    hash::BuildHasher,
     path::{Path, PathBuf},
     rc::Rc as RustRc,
     sync::Arc,
@@ -15,6 +14,7 @@ use dashmap::DashMap;
 use either::Either;
 use indexmap::IndexMap;
 use once_cell::sync::Lazy;
+use rustc_hash::FxHashMap;
 use serde::{
     de::{Unexpected, Visitor},
     Deserialize, Deserializer, Serialize, Serializer,
@@ -28,6 +28,10 @@ use swc_common::{
     errors::Handler,
     FileName, Mark, SourceMap, SyntaxContext,
 };
+use swc_config::{
+    config_types::{BoolConfig, BoolOr, BoolOrDataConfig},
+    merge::Merge,
+};
 use swc_ecma_ast::{EsVersion, Expr, Program};
 use swc_ecma_ext_transforms::jest;
 use swc_ecma_lints::{
@@ -40,7 +44,7 @@ use swc_ecma_loader::{
 };
 use swc_ecma_minifier::option::{
     terser::{TerserCompressorOptions, TerserEcmaVersion, TerserTopLevelOptions},
-    MangleOptions, ManglePropertiesOptions,
+    MangleOptions,
 };
 #[allow(deprecated)]
 pub use swc_ecma_parser::JscTarget;
@@ -61,7 +65,6 @@ use swc_ecma_transforms_compat::es2015::regenerator;
 use swc_ecma_transforms_optimization::{inline_globals2, GlobalExprMap};
 use swc_ecma_visit::{Fold, VisitMutWith};
 
-use self::util::BoolOrObject;
 use crate::{
     builder::PassBuilder,
     dropped_comments_preserver::dropped_comments_preserver,
@@ -71,7 +74,6 @@ use crate::{
 
 #[cfg(test)]
 mod tests;
-pub mod util;
 
 #[derive(Clone, Debug, Copy)]
 pub enum IsModule {
@@ -269,7 +271,6 @@ impl Options {
         output_path: Option<&Path>,
         source_file_name: Option<String>,
         handler: &Handler,
-        is_module: IsModule,
         config: Option<Config>,
         comments: Option<&'a SingleThreadedComments>,
         custom_before_pass: impl FnOnce(&Program) -> P,
@@ -277,11 +278,12 @@ impl Options {
     where
         P: 'a + swc_ecma_visit::Fold,
     {
-        let mut config = config.unwrap_or_default();
+        let mut cfg = self.config.clone();
-        config.merge(&self.config);
+        cfg.merge(config.unwrap_or_default());
+        let is_module = self.is_module;
 
         let mut source_maps = self.source_maps.clone();
-        source_maps.merge(&config.source_maps);
+        source_maps.merge(cfg.source_maps.clone());
 
         let JscConfig {
             assumptions,
@@ -298,7 +300,11 @@ impl Options {
             lints,
             preserve_all_comments,
             ..
-        } = config.jsc;
+        } = cfg.jsc;
+        let loose = loose.into_bool();
+        let preserve_all_comments = preserve_all_comments.into_bool();
+        let keep_class_names = keep_class_names.into_bool();
+        let external_helpers = external_helpers.into_bool();
 
         let mut assumptions = assumptions.unwrap_or_else(|| {
             if loose {
@@ -338,7 +344,10 @@ impl Options {
             js_minify = js_minify.map(|c| {
                 let compress = c
                     .compress
-                    .into_obj()
+                    .unwrap_as_option(|default| match default {
+                        Some(true) => Some(Default::default()),
+                        _ => None,
+                    })
                     .map(|mut c| {
                         if c.toplevel.is_none() {
                             c.toplevel = Some(TerserTopLevelOptions::Bool(true));
@@ -346,19 +355,22 @@ impl Options {
 
                         c
                     })
-                    .map(BoolOrObject::Obj)
+                    .map(BoolOrDataConfig::from_obj)
-                    .unwrap_or(BoolOrObject::Bool(false));
+                    .unwrap_or_else(|| BoolOrDataConfig::from_bool(false));
 
                 let mangle = c
                     .mangle
-                    .into_obj()
+                    .unwrap_as_option(|default| match default {
+                        Some(true) => Some(Default::default()),
+                        _ => None,
+                    })
                     .map(|mut c| {
                         c.top_level = true;
 
                         c
                     })
-                    .map(BoolOrObject::Obj)
+                    .map(BoolOrDataConfig::from_obj)
-                    .unwrap_or(BoolOrObject::Bool(false));
+                    .unwrap_or_else(|| BoolOrDataConfig::from_bool(false));
 
                 JsMinifyOptions {
                     compress,
@@ -371,9 +383,21 @@ impl Options {
         let regenerator = transform.regenerator.clone();
 
         let preserve_comments = if preserve_all_comments {
-            Some(BoolOrObject::from(true))
+            BoolOr::Bool(true)
         } else {
-            js_minify.as_ref().map(|v| v.format.comments.clone())
+            js_minify
+                .as_ref()
+                .map(|v| match v.format.comments.clone().into_inner() {
+                    Some(v) => v,
+                    None => BoolOr::Bool(false),
+                })
+                .unwrap_or_else(|| {
+                    BoolOr::Data(if cfg.minify.into_bool() {
+                        JsMinifyCommentOption::PreserveSomeComments
+                    } else {
+                        JsMinifyCommentOption::PreserveAllComments
+                    })
+                })
         };
 
         if syntax.typescript() {
@@ -397,7 +421,10 @@ impl Options {
             }
         };
 
-        let enable_simplifier = optimizer.as_ref().map(|v| v.simplify).unwrap_or_default();
+        let enable_simplifier = optimizer
+            .as_ref()
+            .map(|v| v.simplify.into_bool())
+            .unwrap_or_default();
 
         let optimization = {
             if let Some(opts) = optimizer.and_then(|o| o.globals) {
@@ -439,18 +466,18 @@ impl Options {
             Some(hygiene::Config { keep_class_names })
         })
         .fixer(!self.disable_fixer)
-        .preset_env(config.env)
+        .preset_env(cfg.env)
         .regenerator(regenerator)
         .finalize(
             base_url,
             paths.into_iter().collect(),
             base,
             syntax,
-            config.module,
+            cfg.module,
             comments,
         );
 
-        let keep_import_assertions = experimental.keep_import_assertions;
+        let keep_import_assertions = experimental.keep_import_assertions.into_bool();
 
         // Embedded runtime plugin target, based on assumption we have
         // 1. filesystem access for the cache
@@ -570,15 +597,15 @@ impl Options {
 
         Ok(BuiltInput {
             program,
-            minify: config.minify,
+            minify: cfg.minify.into_bool(),
             pass,
             external_helpers,
             syntax,
             target: es_version,
             is_module,
             source_maps: source_maps.unwrap_or(SourceMapsConfig::Bool(false)),
-            inline_sources_content: config.inline_sources_content,
+            inline_sources_content: cfg.inline_sources_content.into_bool(),
-            input_source_map: config.input_source_map.clone(),
+            input_source_map: cfg.input_source_map.clone().unwrap_or_default(),
             output_path: output_path.map(|v| v.to_path_buf()),
             source_file_name,
             comments: comments.cloned(),
@@ -648,17 +675,8 @@ impl Default for Rc {
                 exclude: Some(FileMatcher::Regex("\\.tsx?$".into())),
                 jsc: JscConfig {
                     syntax: Some(Default::default()),
-                    transform: None,
-                    external_helpers: false,
-                    target: Default::default(),
-                    loose: false,
-                    keep_class_names: false,
                     ..Default::default()
                 },
-                module: None,
-                minify: false,
-                source_maps: None,
-                input_source_map: InputSourceMap::default(),
                 ..Default::default()
             },
             Config {
@@ -670,17 +688,8 @@ impl Default for Rc {
                         tsx: true,
                         ..Default::default()
                     })),
-                    transform: None,
-                    external_helpers: false,
-                    target: Default::default(),
-                    loose: false,
-                    keep_class_names: false,
                     ..Default::default()
                 },
-                module: None,
-                minify: false,
-                source_maps: None,
-                input_source_map: InputSourceMap::default(),
                 ..Default::default()
             },
             Config {
@@ -692,17 +701,8 @@ impl Default for Rc {
                         tsx: false,
                         ..Default::default()
                     })),
-                    transform: None,
-                    external_helpers: false,
-                    target: Default::default(),
-                    loose: false,
-                    keep_class_names: false,
                     ..Default::default()
                 },
-                module: None,
-                minify: false,
-                source_maps: None,
-                input_source_map: InputSourceMap::default(),
                 ..Default::default()
             },
         ])
@@ -747,7 +747,7 @@ impl Rc {
 }
 
 /// A single object in the `.swcrc` file
-#[derive(Debug, Default, Clone, Deserialize)]
+#[derive(Debug, Default, Clone, Deserialize, Merge)]
 #[serde(deny_unknown_fields, rename_all = "camelCase")]
 pub struct Config {
     #[serde(default)]
@@ -766,17 +766,17 @@ pub struct Config {
     pub module: Option<ModuleConfig>,
 
     #[serde(default)]
-    pub minify: bool,
+    pub minify: BoolConfig<false>,
 
     #[serde(default)]
-    pub input_source_map: InputSourceMap,
+    pub input_source_map: Option<InputSourceMap>,
 
     /// Possible values are: `'inline'`, `true`, `false`.
     #[serde(default)]
     pub source_maps: Option<SourceMapsConfig>,
 
-    #[serde(default = "true_by_default")]
+    #[serde(default)]
-    pub inline_sources_content: bool,
+    pub inline_sources_content: BoolConfig<true>,
 
     #[serde(default)]
     pub error: ErrorConfig,
@@ -790,10 +790,10 @@ pub struct Config {
 #[serde(deny_unknown_fields, rename_all = "camelCase")]
 pub struct JsMinifyOptions {
     #[serde(default)]
-    pub compress: BoolOrObject<TerserCompressorOptions>,
+    pub compress: BoolOrDataConfig<TerserCompressorOptions>,
 
     #[serde(default)]
-    pub mangle: BoolOrObject<MangleOptions>,
+    pub mangle: BoolOrDataConfig<MangleOptions>,
 
     #[serde(default)]
     pub format: JsMinifyFormatOptions,
@@ -817,7 +817,7 @@ pub struct JsMinifyOptions {
     pub toplevel: bool,
 
     #[serde(default)]
-    pub source_map: BoolOrObject<TerserSourceMapOption>,
+    pub source_map: BoolOrDataConfig<TerserSourceMapOption>,
 
     #[serde(default)]
     pub output_path: Option<String>,
@@ -864,7 +864,7 @@ pub struct JsMinifyFormatOptions {
     pub braces: bool,
 
     #[serde(default)]
-    pub comments: BoolOrObject<JsMinifyCommentOption>,
+    pub comments: BoolOrDataConfig<JsMinifyCommentOption>,
 
     /// Not implemented yet.
     #[serde(default)]
@@ -872,7 +872,7 @@ pub struct JsMinifyFormatOptions {
 
     /// Not implemented yet.
     #[serde(default, alias = "indent_level")]
-    pub indent_level: usize,
+    pub indent_level: Option<usize>,
 
     /// Not implemented yet.
     #[serde(default, alias = "indent_start")]
@@ -892,7 +892,7 @@ pub struct JsMinifyFormatOptions {
 
     /// Not implemented yet.
     #[serde(default, alias = "max_line_len")]
-    pub max_line_len: BoolOrObject<usize>,
+    pub max_line_len: usize,
 
     /// Not implemented yet.
     #[serde(default)]
@@ -1054,13 +1054,13 @@ pub struct BuiltInput<P: swc_ecma_visit::Fold> {
     pub source_file_name: Option<String>,
 
     pub comments: Option<SingleThreadedComments>,
-    pub preserve_comments: Option<BoolOrObject<JsMinifyCommentOption>>,
+    pub preserve_comments: BoolOr<JsMinifyCommentOption>,
 
     pub inline_sources_content: bool,
 }
 
 /// `jsc` in  `.swcrc`.
-#[derive(Debug, Default, Clone, Serialize, Deserialize)]
+#[derive(Debug, Default, Clone, Serialize, Deserialize, Merge)]
 #[serde(deny_unknown_fields, rename_all = "camelCase")]
 pub struct JscConfig {
     #[serde(default)]
@@ -1073,16 +1073,16 @@ pub struct JscConfig {
     pub transform: Option<TransformConfig>,
 
     #[serde(default)]
-    pub external_helpers: bool,
+    pub external_helpers: BoolConfig<false>,
 
     #[serde(default)]
     pub target: Option<EsVersion>,
 
     #[serde(default)]
-    pub loose: bool,
+    pub loose: BoolConfig<false>,
 
     #[serde(default)]
-    pub keep_class_names: bool,
+    pub keep_class_names: BoolConfig<false>,
 
     #[serde(default)]
     pub base_url: PathBuf,
@@ -1100,11 +1100,11 @@ pub struct JscConfig {
     pub lints: LintConfig,
 
     #[serde(default)]
-    pub preserve_all_comments: bool,
+    pub preserve_all_comments: BoolConfig<false>,
 }
 
 /// `jsc.experimental` in `.swcrc`
-#[derive(Debug, Default, Clone, Serialize, Deserialize)]
+#[derive(Debug, Default, Clone, Serialize, Deserialize, Merge)]
 #[serde(deny_unknown_fields, rename_all = "camelCase")]
 pub struct JscExperimental {
     /// This requires cargo feature `plugin`.
@@ -1112,7 +1112,7 @@ pub struct JscExperimental {
     pub plugins: Option<Vec<PluginConfig>>,
     /// If true, keeps import assertions in the output.
     #[serde(default)]
-    pub keep_import_assertions: bool,
+    pub keep_import_assertions: BoolConfig<false>,
     /// Location where swc may stores its intermediate cache.
     /// Currently this is only being used for wasm plugin's bytecache.
     /// Path should be absolute directory, which will be created if not exist.
@@ -1122,19 +1122,6 @@ pub struct JscExperimental {
     pub cache_root: Option<String>,
 }
 
-impl Merge for JscExperimental {
-    fn merge(&mut self, from: &Self) {
-        if self.plugins.is_none() {
-            self.plugins = from.plugins.clone();
-        }
-        if self.cache_root.is_none() {
-            self.cache_root = from.cache_root.clone();
-        }
-
-        self.keep_import_assertions |= from.keep_import_assertions;
-    }
-}
-
 /// `paths` section of `tsconfig.json`.
 pub type Paths = IndexMap<String, Vec<String>, ahash::RandomState>;
 pub(crate) type CompiledPaths = Vec<(String, Vec<String>)>;
@@ -1296,21 +1283,21 @@ pub struct HiddenTransformConfig {
     pub jest: bool,
 }
 
-#[derive(Debug, Default, Clone, Serialize, Deserialize)]
+#[derive(Debug, Default, Clone, Serialize, Deserialize, Merge)]
 #[serde(deny_unknown_fields, rename_all = "camelCase")]
 pub struct ConstModulesConfig {
     #[serde(default)]
-    pub globals: HashMap<JsWord, HashMap<JsWord, String>>,
+    pub globals: FxHashMap<JsWord, FxHashMap<JsWord, String>>,
 }
 
-#[derive(Debug, Default, Clone, Serialize, Deserialize)]
+#[derive(Debug, Default, Clone, Serialize, Deserialize, Merge)]
 #[serde(deny_unknown_fields, rename_all = "camelCase")]
 pub struct OptimizerConfig {
     #[serde(default)]
     pub globals: Option<GlobalPassOption>,
 
-    #[serde(default = "true_by_default")]
+    #[serde(default)]
-    pub simplify: bool,
+    pub simplify: BoolConfig<true>,
 
     #[serde(default)]
     pub jsonify: Option<JsonifyOption>,
@@ -1327,15 +1314,10 @@ fn default_jsonify_min_cost() -> usize {
     1024
 }
 
-#[derive(Debug, Clone, Copy, Serialize, Deserialize)]
+#[derive(Debug, Default, Clone, Copy, Serialize, Deserialize, Merge)]
 #[serde(deny_unknown_fields, rename_all = "camelCase")]
 pub struct ErrorConfig {
-    pub filename: bool,
+    pub filename: BoolConfig<true>,
-}
-impl Default for ErrorConfig {
-    fn default() -> Self {
-        ErrorConfig { filename: true }
-    }
 }
 
 #[derive(Debug, Default, Clone, Serialize, Deserialize)]
@@ -1538,284 +1520,6 @@ fn default_env_name() -> String {
     }
 }
 
-pub trait Merge {
-    /// Apply overrides from `from`
-    fn merge(&mut self, from: &Self);
-}
-
-impl<T: Clone> Merge for Option<T>
-where
-    T: Merge,
-{
-    fn merge(&mut self, from: &Option<T>) {
-        if let Some(ref from) = *from {
-            match *self {
-                Some(ref mut v) => v.merge(from),
-                None => *self = Some(from.clone()),
-            }
-        }
-    }
-}
-
-impl Merge for Config {
-    fn merge(&mut self, from: &Self) {
-        self.jsc.merge(&from.jsc);
-        self.module.merge(&from.module);
-        self.minify.merge(&from.minify);
-        self.env.merge(&from.env);
-        self.source_maps.merge(&from.source_maps);
-        self.input_source_map.merge(&from.input_source_map);
-        self.inline_sources_content
-            .merge(&from.inline_sources_content);
-    }
-}
-
-impl Merge for JsMinifyOptions {
-    fn merge(&mut self, from: &Self) {
-        self.compress.merge(&from.compress);
-        self.mangle.merge(&from.mangle);
-        self.format.merge(&from.format);
-        self.ecma.merge(&from.ecma);
-        self.keep_classnames |= from.keep_classnames;
-        self.keep_fnames |= from.keep_fnames;
-        self.safari10 |= from.safari10;
-        self.toplevel |= from.toplevel;
-        self.inline_sources_content |= from.inline_sources_content;
-    }
-}
-
-impl Merge for TerserCompressorOptions {
-    fn merge(&mut self, from: &Self) {
-        self.defaults |= from.defaults;
-        // TODO
-    }
-}
-
-impl Merge for MangleOptions {
-    fn merge(&mut self, from: &Self) {
-        self.props.merge(&from.props);
-
-        self.top_level |= from.top_level;
-        self.keep_class_names |= from.keep_class_names;
-        self.keep_fn_names |= from.keep_fn_names;
-        self.keep_private_props |= from.keep_private_props;
-        self.safari10 |= from.safari10;
-    }
-}
-
-impl Merge for JsMinifyFormatOptions {
-    fn merge(&mut self, from: &Self) {
-        self.comments.merge(&from.comments);
-    }
-}
-
-impl Merge for JsMinifyCommentOption {
-    fn merge(&mut self, _: &Self) {}
-}
-
-impl Merge for ManglePropertiesOptions {
-    fn merge(&mut self, from: &Self) {
-        self.undeclared |= from.undeclared;
-    }
-}
-
-impl Merge for TerserEcmaVersion {
-    fn merge(&mut self, from: &Self) {
-        *self = from.clone();
-    }
-}
-
-impl Merge for SourceMapsConfig {
-    fn merge(&mut self, _: &Self) {}
-}
-
-impl Merge for InputSourceMap {
-    fn merge(&mut self, r: &Self) {
-        if let InputSourceMap::Bool(false) = *self {
-            *self = r.clone();
-        }
-    }
-}
-
-impl Merge for swc_ecma_preset_env::Config {
-    fn merge(&mut self, from: &Self) {
-        *self = from.clone();
-    }
-}
-
-impl Merge for JscConfig {
-    fn merge(&mut self, from: &Self) {
-        self.assumptions.merge(&from.assumptions);
-        self.syntax.merge(&from.syntax);
-        self.transform.merge(&from.transform);
-        self.external_helpers.merge(&from.external_helpers);
-        self.target.merge(&from.target);
-        self.loose.merge(&from.loose);
-        self.keep_class_names.merge(&from.keep_class_names);
-        self.paths.merge(&from.paths);
-        self.minify.merge(&from.minify);
-        self.experimental.merge(&from.experimental);
-        self.preserve_all_comments
-            .merge(&from.preserve_all_comments)
-    }
-}
-
-impl<K, V, S> Merge for IndexMap<K, V, S>
-where
-    K: Clone + Eq + std::hash::Hash,
-    V: Clone,
-    S: Clone + BuildHasher,
-{
-    fn merge(&mut self, from: &Self) {
-        if self.is_empty() {
-            *self = (*from).clone();
-        }
-    }
-}
-
-impl<K, V, S> Merge for HashMap<K, V, S>
-where
-    K: Clone + Eq + std::hash::Hash,
-    V: Clone,
-    S: Clone + BuildHasher,
-{
-    fn merge(&mut self, from: &Self) {
-        if self.is_empty() {
-            *self = (*from).clone();
-        } else {
-            for (k, v) in from {
-                self.entry(k.clone()).or_insert_with(|| v.clone());
-            }
-        }
-    }
-}
-
-impl Merge for EsVersion {
-    fn merge(&mut self, from: &Self) {
-        if *self < *from {
-            *self = *from
-        }
-    }
-}
-
-impl Merge for Option<ModuleConfig> {
-    fn merge(&mut self, from: &Self) {
-        if let Some(ref c2) = *from {
-            *self = Some(c2.clone())
-        }
-    }
-}
-
-impl Merge for bool {
-    fn merge(&mut self, from: &Self) {
-        *self |= *from
-    }
-}
-
-impl Merge for Syntax {
-    fn merge(&mut self, from: &Self) {
-        match (&mut *self, from) {
-            (Syntax::Es(a), Syntax::Es(b)) => {
-                a.merge(b);
-            }
-            (Syntax::Typescript(a), Syntax::Typescript(b)) => {
-                a.merge(b);
-            }
-            _ => {
-                *self = *from;
-            }
-        }
-    }
-}
-
-impl Merge for swc_ecma_parser::EsConfig {
-    fn merge(&mut self, from: &Self) {
-        self.jsx |= from.jsx;
-        self.fn_bind |= from.fn_bind;
-        self.decorators |= from.decorators;
-        self.decorators_before_export |= from.decorators_before_export;
-        self.export_default_from |= from.export_default_from;
-        self.import_assertions |= from.import_assertions;
-        self.private_in_object |= from.private_in_object;
-    }
-}
-
-impl Merge for swc_ecma_parser::TsConfig {
-    fn merge(&mut self, from: &Self) {
-        self.tsx |= from.tsx;
-        self.decorators |= from.decorators;
-    }
-}
-
-impl Merge for Assumptions {
-    fn merge(&mut self, from: &Self) {
-        self.array_like_is_iterable |= from.array_like_is_iterable;
-        self.constant_reexports |= from.constant_reexports;
-        self.constant_super |= from.constant_super;
-        self.enumerable_module_meta |= from.enumerable_module_meta;
-        self.ignore_function_length |= from.ignore_function_length;
-        self.ignore_function_name |= from.ignore_function_name;
-        self.ignore_to_primitive_hint |= from.ignore_to_primitive_hint;
-        self.iterable_is_array |= from.iterable_is_array;
-        self.mutable_template_object |= from.mutable_template_object;
-        self.no_class_calls |= from.no_class_calls;
-        self.no_document_all |= from.no_document_all;
-        self.no_incomplete_ns_import_detection |= from.no_incomplete_ns_import_detection;
-        self.no_new_arrows |= from.no_new_arrows;
-        self.object_rest_no_symbols |= from.object_rest_no_symbols;
-        self.private_fields_as_properties |= from.private_fields_as_properties;
-        self.pure_getters |= from.pure_getters;
-        self.set_class_methods |= from.set_class_methods;
-        self.set_computed_properties |= from.set_computed_properties;
-        self.set_public_class_fields |= from.set_public_class_fields;
-        self.set_spread_properties |= from.set_spread_properties;
-        self.skip_for_of_iterator_closing |= from.skip_for_of_iterator_closing;
-        self.super_is_callable_constructor |= from.super_is_callable_constructor;
-        self.ts_enum_is_readonly |= from.ts_enum_is_readonly;
-    }
-}
-
-impl Merge for TransformConfig {
-    fn merge(&mut self, from: &Self) {
-        self.optimizer.merge(&from.optimizer);
-        self.const_modules.merge(&from.const_modules);
-        self.react.merge(&from.react);
-        self.hidden.merge(&from.hidden);
-    }
-}
-
-impl Merge for OptimizerConfig {
-    fn merge(&mut self, from: &Self) {
-        self.globals.merge(&from.globals)
-    }
-}
-
-impl Merge for GlobalPassOption {
-    fn merge(&mut self, from: &Self) {
-        *self = from.clone();
-    }
-}
-
-impl Merge for react::Options {
-    fn merge(&mut self, from: &Self) {
-        if *from != react::Options::default() {
-            *self = from.clone();
-        }
-    }
-}
-
-impl Merge for ConstModulesConfig {
-    fn merge(&mut self, from: &Self) {
-        *self = from.clone()
-    }
-}
-
-impl Merge for HiddenTransformConfig {
-    fn merge(&mut self, from: &Self) {
-        self.jest |= from.jest;
-    }
-}
-
 fn build_resolver(base_url: PathBuf, paths: CompiledPaths) -> Box<SwcImportResolver> {
     static CACHE: Lazy<DashMap<(PathBuf, CompiledPaths), SwcImportResolver, ahash::RandomState>> =
         Lazy::new(Default::default);

crates/swc/src/config/util.rs

@@ -1,102 +0,0 @@
-use serde::{Deserialize, Serialize};
-
-use super::Merge;
-
-/// Note: `{}` (empty object) is treated as `true`.
-#[derive(Clone, Serialize, Debug)]
-#[serde(untagged)]
-pub enum BoolOrObject<T> {
-    Bool(bool),
-    Obj(T),
-}
-
-impl<T> From<bool> for BoolOrObject<T> {
-    fn from(v: bool) -> Self {
-        BoolOrObject::Bool(v)
-    }
-}
-
-impl<T> Default for BoolOrObject<T> {
-    fn default() -> Self {
-        Self::Bool(false)
-    }
-}
-
-impl<T> BoolOrObject<T> {
-    pub fn into_obj(self) -> Option<T>
-    where
-        T: Default,
-    {
-        match self {
-            BoolOrObject::Bool(true) => Some(Default::default()),
-            BoolOrObject::Bool(false) => None,
-            BoolOrObject::Obj(o) => Some(o),
-        }
-    }
-}
-
-impl<T> Merge for BoolOrObject<T>
-where
-    T: Clone + Merge + Default,
-{
-    fn merge(&mut self, from: &Self) {
-        match self {
-            BoolOrObject::Bool(l) => match from {
-                BoolOrObject::Bool(r) => {
-                    *l |= *r;
-                }
-                BoolOrObject::Obj(_) => *self = from.clone(),
-            },
-            BoolOrObject::Obj(o) => match from {
-                BoolOrObject::Bool(r) => {
-                    if *r {
-                        o.merge(&Default::default())
-                    }
-                }
-                BoolOrObject::Obj(r) => o.merge(r),
-            },
-        }
-    }
-}
-
-impl<'de, T> Deserialize<'de> for BoolOrObject<T>
-where
-    T: Deserialize<'de>,
-{
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        #[derive(Deserialize)]
-        #[serde(untagged)]
-        enum Deser<T> {
-            Bool(bool),
-            Obj(T),
-            EmptyObject(EmptyStruct),
-        }
-
-        #[derive(Deserialize)]
-        #[serde(deny_unknown_fields)]
-        struct EmptyStruct {}
-
-        let content = swc_common::private::serde::de::Content::deserialize(deserializer)?;
-
-        let deserializer =
-            swc_common::private::serde::de::ContentRefDeserializer::<D::Error>::new(&content);
-
-        let res = Deser::deserialize(deserializer);
-
-        match res {
-            Ok(v) => Ok(match v {
-                Deser::Bool(v) => BoolOrObject::Bool(v),
-                Deser::Obj(v) => BoolOrObject::Obj(v),
-                Deser::EmptyObject(_) => BoolOrObject::Bool(true),
-            }),
-            Err(..) => {
-                let d =
-                    swc_common::private::serde::de::ContentDeserializer::<D::Error>::new(content);
-                Ok(BoolOrObject::Obj(T::deserialize(d)?))
-            }
-        }
-    }
-}

crates/swc/src/lib.rs

@@ -120,8 +120,8 @@ use std::{
 
 use anyhow::{bail, Context, Error};
 use atoms::JsWord;
-use common::{collections::AHashMap, comments::SingleThreadedComments, errors::HANDLER, Span};
+use common::{collections::AHashMap, comments::SingleThreadedComments, errors::HANDLER};
-use config::{util::BoolOrObject, IsModule, JsMinifyCommentOption, JsMinifyOptions};
+use config::{IsModule, JsMinifyCommentOption, JsMinifyOptions};
 use json_comments::StripComments;
 use once_cell::sync::Lazy;
 use serde::Serialize;
@@ -135,6 +135,8 @@ use swc_common::{
     sync::Lrc,
     BytePos, FileName, Globals, Mark, SourceFile, SourceMap, Spanned, GLOBALS,
 };
+pub use swc_config::config_types::{BoolConfig, BoolOr, BoolOrDataConfig};
+use swc_config::merge::Merge;
 use swc_ecma_ast::{EsVersion, Ident, Program};
 use swc_ecma_codegen::{self, text_writer::WriteJs, Emitter, Node};
 use swc_ecma_loader::resolvers::{
@@ -159,7 +161,7 @@ use swc_timer::timer;
 
 pub use crate::builder::PassBuilder;
 use crate::config::{
-    BuiltInput, Config, ConfigFile, InputSourceMap, Merge, Options, Rc, RootMode, SourceMapsConfig,
+    BuiltInput, Config, ConfigFile, InputSourceMap, Options, Rc, RootMode, SourceMapsConfig,
 };
 
 mod builder;
@@ -584,74 +586,14 @@ impl SourceMapGenConfig for SwcSourceMapConfig<'_> {
     }
 }
 
-pub fn minify_global_comments(
+pub(crate) fn minify_file_comments(
-    comments: &SwcComments,
-    span: Span,
-    minify: bool,
-    preserve_comments: Option<BoolOrObject<JsMinifyCommentOption>>,
-) {
-    let preserve_comments = preserve_comments.unwrap_or({
-        if minify {
-            BoolOrObject::Obj(JsMinifyCommentOption::PreserveSomeComments)
-        } else {
-            BoolOrObject::Obj(JsMinifyCommentOption::PreserveAllComments)
-        }
-    });
-
-    match preserve_comments {
-        BoolOrObject::Bool(true)
-        | BoolOrObject::Obj(JsMinifyCommentOption::PreserveAllComments) => {}
-
-        BoolOrObject::Obj(JsMinifyCommentOption::PreserveSomeComments) => {
-            let preserve_excl = |pos: &BytePos, vc: &mut Vec<Comment>| -> bool {
-                if *pos < span.lo || *pos >= span.hi {
-                    return true;
-                }
-
-                // Preserve license comments.
-                if vc.iter().any(|c| c.text.contains("@license")) {
-                    return true;
-                }
-
-                vc.retain(|c: &Comment| c.text.starts_with('!'));
-                !vc.is_empty()
-            };
-            comments.leading.retain(preserve_excl);
-            comments.trailing.retain(preserve_excl);
-        }
-
-        BoolOrObject::Bool(false) => {
-            let remove_all_in_range = |pos: &BytePos, _: &mut Vec<Comment>| -> bool {
-                if *pos < span.lo || *pos >= span.hi {
-                    return true;
-                }
-
-                false
-            };
-            comments.leading.retain(remove_all_in_range);
-            comments.trailing.retain(remove_all_in_range);
-        }
-    }
-}
-
-pub fn minify_file_comments(
     comments: &SingleThreadedComments,
-    minify: bool,
+    preserve_comments: BoolOr<JsMinifyCommentOption>,
-    preserve_comments: Option<BoolOrObject<JsMinifyCommentOption>>,
 ) {
-    let preserve_comments = preserve_comments.unwrap_or({
-        if minify {
-            BoolOrObject::Obj(JsMinifyCommentOption::PreserveSomeComments)
-        } else {
-            BoolOrObject::Obj(JsMinifyCommentOption::PreserveAllComments)
-        }
-    });
-
     match preserve_comments {
-        BoolOrObject::Bool(true)
+        BoolOr::Bool(true) | BoolOr::Data(JsMinifyCommentOption::PreserveAllComments) => {}
-        | BoolOrObject::Obj(JsMinifyCommentOption::PreserveAllComments) => {}
 
-        BoolOrObject::Obj(JsMinifyCommentOption::PreserveSomeComments) => {
+        BoolOr::Data(JsMinifyCommentOption::PreserveSomeComments) => {
             let preserve_excl = |_: &BytePos, vc: &mut Vec<Comment>| -> bool {
                 // Preserve license comments.
                 if vc.iter().any(|c| c.text.contains("@license")) {
@@ -667,7 +609,7 @@ pub fn minify_file_comments(
             t.retain(preserve_excl);
         }
 
-        BoolOrObject::Bool(false) => {
+        BoolOr::Bool(false) => {
             let (mut l, mut t) = comments.borrow_all_mut();
             l.clear();
             t.clear();
@@ -725,7 +667,7 @@ impl Compiler {
                                 .context("failed to process config file")?;
 
                             if let Some(config_file) = config_file {
-                                config.merge(&config_file.into_config(Some(path))?)
+                                config.merge(config_file.into_config(Some(path))?)
                             }
 
                             if let Some(c) = &mut config {
@@ -831,7 +773,6 @@ impl Compiler {
                 opts.output_path.as_deref(),
                 opts.source_file_name.clone(),
                 handler,
-                opts.is_module,
                 Some(config),
                 comments,
                 before_pass,
@@ -963,10 +904,10 @@ impl Compiler {
 
             let target = opts.ecma.clone().into();
 
-            let (source_map, orig) = match &opts.source_map {
+            let (source_map, orig) = opts
-                BoolOrObject::Bool(false) => (SourceMapsConfig::Bool(false), None),
+                .source_map
-                BoolOrObject::Bool(true) => (SourceMapsConfig::Bool(true), None),
+                .as_ref()
-                BoolOrObject::Obj(obj) => {
+                .map(|obj| -> Result<_, Error> {
                     let orig = obj
                         .content
                         .as_ref()
@@ -975,17 +916,32 @@ impl Compiler {
                         Some(v) => Some(v?),
                         None => None,
                     };
-                    (SourceMapsConfig::Bool(true), orig)
+                    Ok((SourceMapsConfig::Bool(true), orig))
-                }
+                })
-            };
+                .unwrap_as_option(|v| {
+                    Some(Ok(match v {
+                        Some(true) => (SourceMapsConfig::Bool(true), None),
+                        _ => (SourceMapsConfig::Bool(false), None),
+                    }))
+                })
+                .unwrap()?;
 
             let mut min_opts = MinifyOptions {
                 compress: opts
                     .compress
                     .clone()
-                    .into_obj()
+                    .unwrap_as_option(|default| match default {
+                        Some(true) | None => Some(Default::default()),
+                        _ => None,
+                    })
                     .map(|v| v.into_config(self.cm.clone())),
-                mangle: opts.mangle.clone().into_obj(),
+                mangle: opts
+                    .mangle
+                    .clone()
+                    .unwrap_as_option(|default| match default {
+                        Some(true) | None => Some(Default::default()),
+                        _ => None,
+                    }),
                 ..Default::default()
             };
 
@@ -1065,7 +1021,13 @@ impl Compiler {
                 module.fold_with(&mut fixer(Some(&comments as &dyn Comments)))
             });
 
-            minify_file_comments(&comments, true, Some(opts.format.comments.clone()));
+            let preserve_comments = opts
+                .format
+                .comments
+                .clone()
+                .into_inner()
+                .unwrap_or(BoolOr::Data(JsMinifyCommentOption::PreserveSomeComments));
+            minify_file_comments(&comments, preserve_comments);
 
             self.print(
                 &module,
@@ -1135,7 +1097,7 @@ impl Compiler {
             });
 
             if let Some(comments) = &config.comments {
-                minify_file_comments(comments, config.minify, config.preserve_comments);
+                minify_file_comments(comments, config.preserve_comments);
             }
 
             self.print(

crates/swc/tests/exec.rs

@@ -8,7 +8,7 @@ use std::{
 use anyhow::{bail, Context, Error};
 use swc::{
     config::{Config, JsMinifyOptions, JscConfig, ModuleConfig, Options, SourceMapsConfig},
-    try_with_handler, Compiler, HandlerOpts,
+    try_with_handler, BoolOrDataConfig, Compiler, HandlerOpts,
 };
 use swc_common::{errors::ColorConfig, SourceMap};
 use swc_ecma_ast::EsVersion;
@@ -84,12 +84,12 @@ fn create_matrix(entry: &Path) -> Vec<Options> {
                     jsc: JscConfig {
                         syntax: Some(syntax),
                         transform: None,
-                        external_helpers,
+                        external_helpers: external_helpers.into(),
                         target: Some(target),
                         minify: if minify {
                             Some(JsMinifyOptions {
-                                compress: true.into(),
+                                compress: BoolOrDataConfig::from_bool(true),
-                                mangle: true.into(),
+                                mangle: BoolOrDataConfig::from_bool(true),
                                 format: Default::default(),
                                 ecma: Default::default(),
                                 keep_classnames: Default::default(),
@@ -107,7 +107,7 @@ fn create_matrix(entry: &Path) -> Vec<Options> {
                         ..Default::default()
                     },
                     module: Some(ModuleConfig::CommonJs(Default::default())),
-                    minify,
+                    minify: minify.into(),
                     ..Default::default()
                 },
                 source_maps: if source_map {

crates/swc/tests/projects.rs

@@ -9,7 +9,7 @@ use swc::{
         BuiltInput, Config, IsModule, JscConfig, ModuleConfig, Options, SourceMapsConfig,
         TransformConfig,
     },
-    minify_file_comments, Compiler, TransformOutput,
+    Compiler, TransformOutput,
 };
 use swc_common::{
     chain,
@@ -772,8 +772,6 @@ fn should_visit() {
                 })
             });
 
-            minify_file_comments(&comments, config.minify, config.preserve_comments);
-
             Ok(c.print(
                 &program,
                 None,
@@ -831,7 +829,7 @@ fn tests(input_dir: PathBuf) {
                         output_path: Some(output.join(entry.file_name())),
                         config: Config {
                             jsc: JscConfig {
-                                external_helpers: true,
+                                external_helpers: true.into(),
                                 ..Default::default()
                             },
                             ..Default::default()

crates/swc/tests/rust_api.rs

@@ -139,23 +139,23 @@ fn shopify_2_same_opt() {
                         no_early_errors: false,
                     })),
                     transform: None,
-                    external_helpers: false,
+                    external_helpers: false.into(),
                     target: Some(EsVersion::Es5),
-                    loose: false,
+                    loose: false.into(),
-                    keep_class_names: false,
+                    keep_class_names: false.into(),
                     base_url: Default::default(),
                     paths: Default::default(),
                     minify: None,
                     experimental: Default::default(),
                     lints: Default::default(),
                     assumptions: Default::default(),
-                    preserve_all_comments: false,
+                    preserve_all_comments: false.into(),
                 },
                 module: None,
-                minify: false,
+                minify: false.into(),
-                input_source_map: InputSourceMap::Bool(false),
+                input_source_map: Some(InputSourceMap::Bool(false)),
                 source_maps: None,
-                inline_sources_content: false,
+                inline_sources_content: false.into(),
                 ..Default::default()
             },
             skip_helper_injection: false,
@@ -218,10 +218,10 @@ fn shopify_3_reduce_defaults() {
                     ..Default::default()
                 },
                 module: None,
-                minify: false,
+                minify: false.into(),
-                input_source_map: InputSourceMap::Bool(false),
+                input_source_map: InputSourceMap::Bool(false).into(),
                 source_maps: None,
-                inline_sources_content: false,
+                inline_sources_content: false.into(),
                 ..Default::default()
             },
             cwd: "/Users/kdy1/projects/example-swcify".into(),

crates/swc/tests/source_map.rs

@@ -30,7 +30,7 @@ fn file(f: &str) -> Result<(), StdErr> {
                 &handler,
                 &Options {
                     config: Config {
-                        inline_sources_content: true,
+                        inline_sources_content: true.into(),
                         ..Default::default()
                     },
                     swcrc: true,
@@ -85,7 +85,7 @@ fn inline(f: &str) -> Result<(), StdErr> {
                 &handler,
                 &Options {
                     config: Config {
-                        inline_sources_content: true,
+                        inline_sources_content: true.into(),
                         ..Default::default()
                     },
                     swcrc: true,

crates/swc/tests/tsc.rs

@@ -137,9 +137,9 @@ fn compile(input: &Path, output: &Path, opts: Options) {
                                 tsx: input.to_string_lossy().ends_with(".tsx"),
                                 decorators: true,
                                 dts: false,
-                                no_early_errors: true,
+                                no_early_errors: false,
                             })),
-                            external_helpers: true,
+                            external_helpers: true.into(),
                             ..opts.config.jsc
                         },
                         source_maps: Some(SourceMapsConfig::Bool(

crates/swc_config/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+authors = ["강동윤 <kdy1997.dev@gmail.com>"]
+description = "Types for configuring swc"
+documentation = "https://rustdoc.swc.rs/swc_config/"
+edition = "2021"
+license = "Apache-2.0"
+name = "swc_config"
+repository = "https://github.com/swc-project/swc.git"
+version = "0.1.0"
+
+[dependencies]
+anyhow = "1"
+indexmap = "1"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+swc_config_macro = { version = "0.1.0", path = "../swc_config_macro" }

crates/swc_config/src/config_types/bool_config.rs

@@ -0,0 +1,51 @@
+use serde::{Deserialize, Serialize};
+
+use crate::merge::Merge;
+
+#[derive(
+    Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize,
+)]
+pub struct BoolConfig<const DEFAULT: bool>(#[serde(default)] Option<bool>);
+
+impl<const DEFAULT: bool> BoolConfig<DEFAULT> {
+    #[inline]
+    pub fn new(value: Option<bool>) -> Self {
+        Self(value)
+    }
+
+    #[inline]
+    pub fn into_bool(self) -> bool {
+        self.into()
+    }
+}
+
+impl<const DEFAULT: bool> From<BoolConfig<DEFAULT>> for bool {
+    #[inline]
+    fn from(v: BoolConfig<DEFAULT>) -> Self {
+        match v.0 {
+            Some(v) => v,
+            _ => DEFAULT,
+        }
+    }
+}
+
+impl<const DEFAULT: bool> From<Option<bool>> for BoolConfig<DEFAULT> {
+    #[inline]
+    fn from(v: Option<bool>) -> Self {
+        Self(v)
+    }
+}
+
+impl<const DEFAULT: bool> From<bool> for BoolConfig<DEFAULT> {
+    #[inline]
+    fn from(v: bool) -> Self {
+        Self(Some(v))
+    }
+}
+
+impl<const DEFAULT: bool> Merge for BoolConfig<DEFAULT> {
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        self.0.merge(other.0);
+    }
+}

crates/swc_config/src/config_types/bool_or_data.rs

@@ -0,0 +1,140 @@
+use serde::{Deserialize, Serialize};
+
+use crate::merge::Merge;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+pub struct BoolOrDataConfig<T>(#[serde(default)] Option<BoolOr<T>>);
+
+impl<T> BoolOrDataConfig<T> {
+    pub fn from_bool(v: bool) -> Self {
+        Self(Some(BoolOr::Bool(v)))
+    }
+
+    pub fn from_obj(v: T) -> Self {
+        v.into()
+    }
+
+    pub fn as_ref(&self) -> BoolOrDataConfig<&T> {
+        match &self.0 {
+            Some(BoolOr::Data(v)) => BoolOrDataConfig::from_obj(v),
+            Some(BoolOr::Bool(b)) => BoolOrDataConfig::from_bool(*b),
+            None => BoolOrDataConfig::default(),
+        }
+    }
+
+    pub fn or<F>(self, default: F) -> Self
+    where
+        F: FnOnce() -> Self,
+    {
+        match self.0 {
+            Some(..) => self,
+            None => default(),
+        }
+    }
+
+    pub fn unwrap_as_option<F>(self, default: F) -> Option<T>
+    where
+        F: FnOnce(Option<bool>) -> Option<T>,
+    {
+        match self.0 {
+            Some(BoolOr::Data(v)) => Some(v),
+            Some(BoolOr::Bool(b)) => default(Some(b)),
+            None => default(None),
+        }
+    }
+
+    pub fn map<F, N>(self, op: F) -> BoolOrDataConfig<N>
+    where
+        F: FnOnce(T) -> N,
+    {
+        match self.0 {
+            Some(BoolOr::Data(v)) => BoolOrDataConfig::from_obj(op(v)),
+            Some(BoolOr::Bool(b)) => BoolOrDataConfig::from_bool(b),
+            None => BoolOrDataConfig::default(),
+        }
+    }
+
+    pub fn is_true(&self) -> bool {
+        matches!(self.0, Some(BoolOr::Bool(true)))
+    }
+
+    pub fn is_false(&self) -> bool {
+        matches!(self.0, Some(BoolOr::Bool(false)))
+    }
+
+    pub fn is_obj(&self) -> bool {
+        matches!(self.0, Some(BoolOr::Data(_)))
+    }
+
+    pub fn into_inner(self) -> Option<BoolOr<T>> {
+        self.0
+    }
+}
+
+impl<T> From<T> for BoolOrDataConfig<T> {
+    fn from(v: T) -> Self {
+        Self(Some(BoolOr::Data(v)))
+    }
+}
+
+impl<T> Default for BoolOrDataConfig<T> {
+    fn default() -> Self {
+        Self(Default::default())
+    }
+}
+
+impl<T> Merge for BoolOrDataConfig<T> {
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        self.0.merge(other.0)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize)]
+#[serde(untagged)]
+pub enum BoolOr<T> {
+    Bool(bool),
+    Data(T),
+}
+
+impl<'de, T> Deserialize<'de> for BoolOr<T>
+where
+    T: Deserialize<'de>,
+{
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        #[derive(Deserialize)]
+        #[serde(untagged)]
+        enum Deser<T> {
+            Bool(bool),
+            Obj(T),
+            EmptyObject(EmptyStruct),
+        }
+
+        #[derive(Deserialize)]
+        #[serde(deny_unknown_fields)]
+        struct EmptyStruct {}
+
+        use serde::__private::de;
+
+        let content = de::Content::deserialize(deserializer)?;
+
+        let deserializer = de::ContentRefDeserializer::<D::Error>::new(&content);
+
+        let res = Deser::deserialize(deserializer);
+
+        match res {
+            Ok(v) => Ok(match v {
+                Deser::Bool(v) => BoolOr::Bool(v),
+                Deser::Obj(v) => BoolOr::Data(v),
+                Deser::EmptyObject(_) => BoolOr::Bool(true),
+            }),
+            Err(..) => {
+                let d = de::ContentDeserializer::<D::Error>::new(content);
+                Ok(BoolOr::Data(T::deserialize(d)?))
+            }
+        }
+    }
+}

crates/swc_config/src/config_types/mod.rs

@@ -0,0 +1,7 @@
+pub use self::{
+    bool_config::BoolConfig,
+    bool_or_data::{BoolOr, BoolOrDataConfig},
+};
+
+mod bool_config;
+mod bool_or_data;

crates/swc_config/src/lib.rs

@@ -0,0 +1,4 @@
+#[macro_use]
+mod macros;
+pub mod config_types;
+pub mod merge;

crates/swc_config/src/macros.rs

@@ -0,0 +1 @@
+

crates/swc_config/src/merge.rs

@@ -0,0 +1,83 @@
+use std::{collections::HashMap, path::PathBuf};
+
+use indexmap::IndexMap;
+pub use swc_config_macro::Merge;
+
+/// Deriavable trait for overrding configurations.
+///
+/// Typically, correct implementation of this trait for a struct is calling
+/// merge for all fields, and `#[derive(Merge)]` will do it for you.
+pub trait Merge: Sized {
+    /// `self` has higher priority.
+    fn merge(&mut self, other: Self);
+}
+
+/// Modifies `self` iff `self` is [None]
+impl<T> Merge for Option<T> {
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        if self.is_none() {
+            *self = other;
+        }
+    }
+}
+
+impl<T> Merge for Box<T>
+where
+    T: Merge,
+{
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        (**self).merge(*other);
+    }
+}
+
+/// Modifies `self` iff `self` is empty.
+impl<T> Merge for Vec<T> {
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        if self.is_empty() {
+            *self = other;
+        }
+    }
+}
+
+/// Modifies `self` iff `self` is empty.
+impl<K, V, S> Merge for HashMap<K, V, S> {
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        if self.is_empty() {
+            *self = other;
+        }
+    }
+}
+
+/// Modifies `self` iff `self` is empty.
+impl<K, V, S> Merge for IndexMap<K, V, S> {
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        if self.is_empty() {
+            *self = other;
+        }
+    }
+}
+
+/// Modifies `self` iff `self` is empty.
+impl Merge for String {
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        if self.is_empty() {
+            *self = other;
+        }
+    }
+}
+
+/// Modifies `self` iff `self` is empty.
+impl Merge for PathBuf {
+    #[inline]
+    fn merge(&mut self, other: Self) {
+        if self.as_os_str().is_empty() {
+            *self = other;
+        }
+    }
+}

crates/swc_config/tests/config_types.rs

@@ -0,0 +1,29 @@
+use serde_json::Value;
+use swc_config::config_types::BoolConfig;
+
+fn bool_config(v: Value) -> BoolConfig<false> {
+    serde_json::from_value(v).unwrap()
+}
+
+#[test]
+fn test_bool_config_serde() {
+    assert_eq!(bool_config(Value::Null), BoolConfig::new(None));
+
+    assert_eq!(bool_config(Value::Bool(true)), BoolConfig::new(Some(true)));
+    assert_eq!(
+        bool_config(Value::Bool(false)),
+        BoolConfig::new(Some(false))
+    );
+}
+
+#[test]
+fn test_bool_config_default() {
+    assert_eq!(
+        BoolConfig::<false>::default(),
+        BoolConfig::<false>::new(None)
+    );
+    assert_eq!(BoolConfig::<true>::default(), BoolConfig::<true>::new(None));
+
+    assert!(!BoolConfig::<false>::default().into_bool());
+    assert!(BoolConfig::<true>::default().into_bool());
+}

crates/swc_config/tests/derive_merge.rs

@@ -0,0 +1,24 @@
+use swc_config::merge::Merge;
+
+#[derive(Merge)]
+struct Fields {
+    a: Option<()>,
+}
+
+#[test]
+fn test_fields() {
+    let mut fields = Fields { a: None };
+    fields.merge(Fields { a: Some(()) });
+
+    assert_eq!(fields.a, Some(()));
+}
+
+#[derive(Merge)]
+struct Tuple(Option<()>);
+#[test]
+fn test_tuple() {
+    let mut tuple = Tuple(None);
+    tuple.merge(Tuple(Some(())));
+
+    assert_eq!(tuple.0, Some(()));
+}

crates/swc_config_macro/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+authors = ["강동윤 <kdy1997.dev@gmail.com>"]
+description = "Macros to prevent mistakes"
+documentation = "https://rustdoc.swc.rs/swc_config_macro/"
+edition = "2021"
+license = "Apache-2.0"
+name = "swc_config_macro"
+repository = "https://github.com/swc-project/swc.git"
+version = "0.1.0"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+pmutil = "0.5.3"
+proc-macro2 = "1"
+quote = "1"
+swc_macros_common = { version = "0.3.5", path = "../swc_macros_common" }
+syn = "1"

crates/swc_config_macro/src/lib.rs

@@ -0,0 +1,10 @@
+extern crate proc_macro;
+
+mod merge;
+
+#[proc_macro_derive(Merge)]
+pub fn derive_merge(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let input = syn::parse(input).expect("failed to parse input as DeriveInput");
+
+    self::merge::expand(input).into()
+}

crates/swc_config_macro/src/merge.rs

@@ -0,0 +1,64 @@
+use pmutil::{q, SpanExt};
+use proc_macro2::TokenStream;
+use quote::ToTokens;
+use swc_macros_common::{access_field, join_stmts};
+use syn::{DeriveInput, Expr, Field, Fields, Stmt};
+
+pub fn expand(input: DeriveInput) -> TokenStream {
+    match &input.data {
+        syn::Data::Struct(s) => {
+            let body = call_merge_for_fields(&q!({ self }), &s.fields);
+            let body = join_stmts(&body);
+
+            q!(
+                Vars {
+                    Type: &input.ident,
+                    body
+                },
+                {
+                    #[automatically_derived]
+                    impl swc_config::merge::Merge for Type {
+                        fn merge(&mut self, _other: Self) {
+                            body
+                        }
+                    }
+                }
+            )
+            .into()
+        }
+        syn::Data::Enum(_) => unimplemented!("derive(Merge) does not support an enum"),
+        syn::Data::Union(_) => unimplemented!("derive(Merge) does not support a union"),
+    }
+}
+
+fn call_merge_for_fields(obj: &dyn ToTokens, fields: &Fields) -> Vec<Stmt> {
+    fn call_merge(obj: &dyn ToTokens, idx: usize, f: &Field) -> Expr {
+        let r = q!({ _other });
+        q!(
+            Vars {
+                l: access_field(obj, idx, f),
+                r: access_field(&r, idx, f),
+            },
+            { swc_config::merge::Merge::merge(&mut l, r) }
+        )
+        .parse()
+    }
+
+    match fields {
+        Fields::Named(fs) => fs
+            .named
+            .iter()
+            .enumerate()
+            .map(|(idx, f)| call_merge(obj, idx, f))
+            .map(|expr| Stmt::Semi(expr, fs.brace_token.span.as_token()))
+            .collect(),
+        Fields::Unnamed(fs) => fs
+            .unnamed
+            .iter()
+            .enumerate()
+            .map(|(idx, f)| call_merge(obj, idx, f))
+            .map(|expr| Stmt::Semi(expr, fs.paren_token.span.as_token()))
+            .collect(),
+        Fields::Unit => unimplemented!("derive(Merge) does not support a unit struct"),
+    }
+}

crates/swc_ecma_lints/Cargo.toml

@@ -24,6 +24,7 @@ swc_atoms = { version = "0.2.9", path = "../swc_atoms" }
 swc_common = { version = "0.17.23", path = "../swc_common", features = [
   "concurrent",
 ] }
+swc_config = { version = "0.1.0", path = "../swc_config" }
 swc_ecma_ast = { version = "0.77.0", path = "../swc_ecma_ast" }
 swc_ecma_utils = { version = "0.83.0", path = "../swc_ecma_utils" }
 swc_ecma_visit = { version = "0.63.0", path = "../swc_ecma_visit" }

crates/swc_ecma_lints/src/config.rs

@@ -1,6 +1,7 @@
 use std::fmt::Debug;
 
 use serde::{Deserialize, Serialize};
+use swc_config::merge::Merge;
 
 #[cfg(feature = "non_critical_lints")]
 use crate::rules::non_critical_lints::{
@@ -32,11 +33,12 @@ impl Default for LintRuleReaction {
 enum LintRuleLevel {
     Str(LintRuleReaction),
     Number(u8),
+    Unspecified,
 }
 
 impl Default for LintRuleLevel {
     fn default() -> Self {
-        Self::Str(LintRuleReaction::Off)
+        Self::Unspecified
     }
 }
 
@@ -49,6 +51,7 @@ impl From<LintRuleLevel> for LintRuleReaction {
                 2 => LintRuleReaction::Error,
                 _ => LintRuleReaction::Off,
             },
+            LintRuleLevel::Unspecified => LintRuleReaction::Off,
         }
     }
 }
@@ -69,7 +72,19 @@ impl<T: Debug + Clone + Serialize + Default> RuleConfig<T> {
     }
 }
 
-#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+impl<T> Merge for RuleConfig<T>
+where
+    T: Debug + Clone + Serialize + Default,
+{
+    fn merge(&mut self, other: Self) {
+        if let LintRuleLevel::Unspecified = self.0 {
+            self.0 = other.0;
+            self.1 = other.1;
+        }
+    }
+}
+
+#[derive(Debug, Clone, Default, Serialize, Deserialize, Merge)]
 #[non_exhaustive]
 #[serde(rename_all = "kebab-case")]
 pub struct LintConfig {

crates/swc_ecma_minifier/Cargo.toml

@@ -37,6 +37,7 @@ serde_json = "1.0.61"
 swc_atoms = { version = "0.2", path = "../swc_atoms" }
 swc_cached = { version = "0.1.0", path = "../swc_cached" }
 swc_common = { version = "0.17.23", path = "../swc_common" }
+swc_config = { version = "0.1.0", path = "../swc_config" }
 swc_ecma_ast = { version = "0.77.0", path = "../swc_ecma_ast" }
 swc_ecma_codegen = { version = "0.106.0", path = "../swc_ecma_codegen" }
 swc_ecma_parser = { version = "0.103.0", path = "../swc_ecma_parser" }

crates/swc_ecma_minifier/src/option/mod.rs

@@ -2,6 +2,7 @@ use serde::{Deserialize, Serialize};
 use swc_atoms::JsWord;
 use swc_cached::regex::CachedRegex;
 use swc_common::{collections::AHashMap, Mark};
+use swc_config::merge::Merge;
 use swc_ecma_ast::{EsVersion, Expr};
 
 pub mod terser;
@@ -68,13 +69,13 @@ pub struct MangleOptions {
     pub reserved: Vec<JsWord>,
 }
 
-#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+#[derive(Debug, Clone, Default, Serialize, Deserialize, Merge)]
 #[serde(rename_all = "camelCase")]
 pub struct ManglePropertiesOptions {
     #[serde(default, alias = "reserved")]
     pub reserved: Vec<JsWord>,
     #[serde(default, alias = "undeclared")]
-    pub undeclared: bool,
+    pub undeclared: Option<bool>,
     #[serde(default)]
     pub regex: Option<CachedRegex>,
 }

crates/swc_ecma_minifier/tests/mangle.rs

@@ -75,9 +75,7 @@ fn compressed(compressed_file: PathBuf) {
             &MinifyOptions {
                 mangle: Some(MangleOptions {
                     props: Some(ManglePropertiesOptions {
-                        reserved: Default::default(),
+                        ..Default::default()
-                        undeclared: false,
-                        regex: Default::default(),
                     }),
                     top_level: true,
                     keep_class_names: false,

crates/swc_ecma_transforms_optimization/Cargo.toml

@@ -21,23 +21,24 @@ ahash = "0.7.4"
 dashmap = "5.1.0"
 indexmap = "1.6.1"
 once_cell = "1.10.0"
-rayon = {version = "1.5.1", optional = true}
+rayon = { version = "1.5.1", optional = true }
+rustc-hash = "1.1.0"
 serde_json = "1.0.61"
-swc_atoms = {version = "0.2", path = "../swc_atoms"}
+swc_atoms = { version = "0.2", path = "../swc_atoms" }
-swc_common = {version = "0.17.23", path = "../swc_common"}
+swc_common = { version = "0.17.23", path = "../swc_common" }
-swc_ecma_ast = {version = "0.77.0", path = "../swc_ecma_ast"}
+swc_ecma_ast = { version = "0.77.0", path = "../swc_ecma_ast" }
-swc_ecma_parser = {version = "0.103.0", path = "../swc_ecma_parser"}
+swc_ecma_parser = { version = "0.103.0", path = "../swc_ecma_parser" }
-swc_ecma_transforms_base = {version = "0.82.0", path = "../swc_ecma_transforms_base"}
+swc_ecma_transforms_base = { version = "0.82.0", path = "../swc_ecma_transforms_base" }
-swc_ecma_transforms_macros = {version = "0.3.0", path = "../swc_ecma_transforms_macros"}
+swc_ecma_transforms_macros = { version = "0.3.0", path = "../swc_ecma_transforms_macros" }
-swc_ecma_utils = {version = "0.83.0", path = "../swc_ecma_utils"}
+swc_ecma_utils = { version = "0.83.0", path = "../swc_ecma_utils" }
-swc_ecma_visit = {version = "0.63.0", path = "../swc_ecma_visit"}
+swc_ecma_visit = { version = "0.63.0", path = "../swc_ecma_visit" }
 tracing = "0.1.32"
 
 [dev-dependencies]
-swc_ecma_transforms_compat = {version = "0.96.0", path = "../swc_ecma_transforms_compat"}
+swc_ecma_transforms_compat = { version = "0.96.0", path = "../swc_ecma_transforms_compat" }
-swc_ecma_transforms_module = {version = "0.109.0", path = "../swc_ecma_transforms_module"}
+swc_ecma_transforms_module = { version = "0.109.0", path = "../swc_ecma_transforms_module" }
-swc_ecma_transforms_proposal = {version = "0.104.0", path = "../swc_ecma_transforms_proposal"}
+swc_ecma_transforms_proposal = { version = "0.104.0", path = "../swc_ecma_transforms_proposal" }
-swc_ecma_transforms_react = {version = "0.111.0", path = "../swc_ecma_transforms_react"}
+swc_ecma_transforms_react = { version = "0.111.0", path = "../swc_ecma_transforms_react" }
-swc_ecma_transforms_testing = {version = "0.84.0", path = "../swc_ecma_transforms_testing"}
+swc_ecma_transforms_testing = { version = "0.84.0", path = "../swc_ecma_transforms_testing" }
-swc_ecma_transforms_typescript = {version = "0.114.0", path = "../swc_ecma_transforms_typescript"}
+swc_ecma_transforms_typescript = { version = "0.114.0", path = "../swc_ecma_transforms_typescript" }
-testing = {version = "0.19.0", path = "../testing"}
+testing = { version = "0.19.0", path = "../testing" }

crates/swc_ecma_transforms_optimization/src/const_modules.rs

@@ -2,6 +2,7 @@ use std::{collections::HashMap, sync::Arc};
 
 use dashmap::DashMap;
 use once_cell::sync::Lazy;
+use rustc_hash::FxHashMap;
 use swc_atoms::JsWord;
 use swc_common::{errors::HANDLER, sync::Lrc, util::move_map::MoveMap, FileName, SourceMap};
 use swc_ecma_ast::*;
@@ -11,7 +12,7 @@ use swc_ecma_visit::{noop_fold_type, Fold, FoldWith};
 
 pub fn const_modules(
     cm: Lrc<SourceMap>,
-    globals: HashMap<JsWord, HashMap<JsWord, String>>,
+    globals: FxHashMap<JsWord, FxHashMap<JsWord, String>>,
 ) -> impl Fold {
     ConstModules {
         globals: globals

crates/swc_macros_common/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2021"
 license = "Apache-2.0"
 name = "swc_macros_common"
 repository = "https://github.com/swc-project/swc.git"
-version = "0.3.4"
+version = "0.3.5"
 
 [lib]
 bench = false

crates/swc_macros_common/src/lib.rs

@@ -1,9 +1,10 @@
 extern crate proc_macro;
 
-use pmutil::synom_ext::FromSpan;
 #[cfg(procmacro2_semver_exempt)]
 use pmutil::SpanExt;
+use pmutil::{synom_ext::FromSpan, Quote, SpanExt};
 use proc_macro2::Span;
+use quote::ToTokens;
 use syn::*;
 
 pub mod binder;
@@ -78,6 +79,32 @@ pub fn doc_str(attr: &Attribute) -> Option<String> {
     Some(parse_tts(attr))
 }
 
+pub fn access_field(obj: &dyn ToTokens, idx: usize, f: &Field) -> Expr {
+    Expr::Field(ExprField {
+        attrs: Default::default(),
+        base: syn::parse2(obj.to_token_stream())
+            .expect("swc_macros_common::access_field: failed to parse object"),
+        dot_token: Span::call_site().as_token(),
+        member: match &f.ident {
+            Some(id) => Member::Named(id.clone()),
+            _ => Member::Unnamed(Index {
+                index: idx as _,
+                span: Span::call_site(),
+            }),
+        },
+    })
+}
+
+pub fn join_stmts(stmts: &[Stmt]) -> Quote {
+    let mut q = Quote::new_call_site();
+
+    for s in stmts {
+        q.push_tokens(s);
+    }
+
+    q
+}
+
 /// fail! is a panic! with location reporting.
 #[macro_export]
 macro_rules! fail {

crates/swc_node_bundler/src/loaders/swc.rs

@@ -202,12 +202,12 @@ impl SwcLoader {
                                         ..Default::default()
                                     })
                                 },
-                                external_helpers: true,
+                                external_helpers: true.into(),
                                 ..c.jsc.clone()
                             },
                             module: None,
-                            minify: false,
+                            minify: false.into(),
-                            input_source_map: InputSourceMap::Bool(false),
+                            input_source_map: InputSourceMap::Bool(false).into(),
                             ..c.clone()
                         }
                     },

node-swc/__tests__/minify_test.mjs

@@ -6,9 +6,7 @@ it("should compress", async () => {
     console.log(foo)
     `);
 
-    expect(code).toMatchInlineSnapshot(
+    expect(code).toMatchInlineSnapshot(`"import a from\\"@src/app\\";console.log(a)"`);
-        `"import foo from\\"@src/app\\";console.log(foo)"`
-    );
 });
 
 it("should accept object", async () => {
@@ -20,9 +18,7 @@ it("should accept object", async () => {
         {}
     );
 
-    expect(code).toMatchInlineSnapshot(
+    expect(code).toMatchInlineSnapshot(`"import a from\\"@src/app\\";console.log(a)"`);
-        `"import foo from\\"@src/app\\";console.log(foo)"`
-    );
 });
 
 it("should accept { mangle = true }", async () => {

node-swc/__tests__/transform/api_test.js

@@ -176,18 +176,16 @@ it("should respect `error.filename = false`", async () => {
 
 });
 
-it("should merge parser config", async () => {
+it("should support overring `jsc.externalHelpers` using js api", async () => {
     const filename = path.resolve(
-        __dirname + "/../../tests/issue-2546/input.ts"
+        __dirname + "/../../tests/issue-3834/input.js"
     );
 
     const { code } = await swc.transformFile(filename, {
         jsc: {
-            parser: {
+            externalHelpers: false,
-                syntax: "typescript",
-            }
         }
     })
 
-    expect(code).not.toBeFalsy()
+    expect(code).toContain('function _classCallCheck')
 });

node-swc/src/binding.d.ts

@@ -5,7 +5,7 @@
 
 export interface TransformOutput {
   code: string
-  map?: string | undefined | null
+  map?: string
 }
 export function bundle(confItems: Buffer, signal?: AbortSignal | undefined | null): Promise<{ [index: string]: { code: string, map?: string } }>
 export function minify(code: Buffer, opts: Buffer, signal?: AbortSignal | undefined | null): Promise<TransformOutput>
@@ -25,7 +25,7 @@ export function initCustomTraceSubscriber(traceOutFilePath?: string | undefined
 /** Hack for `Type Generation` */
 export interface TransformOutput {
   code: string
-  map?: string | undefined | null
+  map?: string
 }
 export type JsCompiler = Compiler
 export class Compiler {

node-swc/tests/issue-3834/.swcrc

@@ -0,0 +1,8 @@
+{
+    "jsc": {
+        "externalHelpers": true
+    },
+    "module": {
+        "type": "commonjs"
+    }
+}

node-swc/tests/issue-3834/input.js

@@ -0,0 +1,4 @@
+
+
+export default class MyClass {
+}