Add customizable api (#1006)

ecmascript/transforms/src/pass.rs

@@ -1,13 +1,24 @@
 use swc_common::pass::CompilerPass;
 pub use swc_common::pass::{Optional, Repeated};
+use swc_ecma_ast::{Module, Script};
 use swc_ecma_visit::Fold;
 
 pub fn noop() -> impl Fold {
-    struct Noop;
-    impl Fold for Noop {}
     Noop
 }
 
+struct Noop;
+impl Fold for Noop {
+    #[inline(always)]
+    fn fold_module(&mut self, m: Module) -> Module {
+        m
+    }
+    #[inline(always)]
+    fn fold_script(&mut self, s: Script) -> Script {
+        s
+    }
+}
+
 pub trait JsPass: CompilerPass + Fold {}
 
 impl<T: ?Sized> JsPass for T where T: CompilerPass + Fold {}

src/builder.rs

@@ -112,7 +112,6 @@ impl<'a, 'b, P: swc_ecma_visit::Fold> PassBuilder<'a, 'b, P> {
     ///  - fixer if enabled
     pub fn finalize<'cmt>(
         self,
-        root_mark: Mark,
         syntax: Syntax,
         module: Option<ModuleConfig>,
         comments: Option<&'cmt dyn Comments>,
@@ -183,7 +182,7 @@ impl<'a, 'b, P: swc_ecma_visit::Fold> PassBuilder<'a, 'b, P> {
                 need_interop_analysis
             ),
             helpers::inject_helpers(),
-            ModuleConfig::build(self.cm.clone(), root_mark, module),
+            ModuleConfig::build(self.cm.clone(), self.global_mark, module),
             Optional::new(hygiene(), self.hygiene),
             Optional::new(fixer(comments), self.fixer),
         )

src/config.rs

@@ -250,7 +250,7 @@ impl Options {
             .hygiene(!self.disable_hygiene)
             .fixer(!self.disable_fixer)
             .preset_env(config.env)
-            .finalize(root_mark, syntax, config.module, comments);
+            .finalize(syntax, config.module, comments);
 
         BuiltConfig {
             minify: config.minify.unwrap_or(false),

src/lib.rs

@@ -17,6 +17,7 @@ use std::{
     sync::Arc,
 };
 use swc_common::{
+    chain,
     comments::{Comment, Comments},
     errors::Handler,
     input::StringInput,
@@ -27,6 +28,7 @@ use swc_ecma_codegen::{self, Emitter, Node};
 use swc_ecma_parser::{lexer::Lexer, Parser, Syntax};
 use swc_ecma_transforms::{
     helpers::{self, Helpers},
+    pass::noop,
     util,
 };
 use swc_ecma_visit::FoldWith;
@@ -386,13 +388,28 @@ impl Compiler {
         })
     }
 
-    pub fn process_js_file(
+    /// `custom_after_pass` is applied after swc transforms are applied.
+    pub fn process_js_with_custom_pass<P>(
         &self,
         fm: Arc<SourceFile>,
         opts: &Options,
-    ) -> Result<TransformOutput, Error> {
+        custom_after_pass: P,
+    ) -> Result<TransformOutput, Error>
+    where
+        P: swc_ecma_visit::Fold,
+    {
         self.run(|| -> Result<_, Error> {
             let config = self.run(|| self.config_for_file(opts, &fm.name))?;
+            let config = BuiltConfig {
+                pass: chain!(config.pass, custom_after_pass),
+                syntax: config.syntax,
+                target: config.target,
+                minify: config.minify,
+                external_helpers: config.external_helpers,
+                source_maps: config.source_maps,
+                input_source_map: config.input_source_map,
+                is_module: config.is_module,
+            };
             let orig = self.get_orig_src_map(&fm, &opts.input_source_map)?;
             let program = self.parse_js(
                 fm.clone(),
@@ -407,6 +424,14 @@ impl Compiler {
         .context("failed to process js file")
     }
 
+    pub fn process_js_file(
+        &self,
+        fm: Arc<SourceFile>,
+        opts: &Options,
+    ) -> Result<TransformOutput, Error> {
+        self.process_js_with_custom_pass(fm, opts, noop())
+    }
+
     /// You can use custom pass with this method.
     ///
     /// There exists a [PassBuilder] to help building custom passes.