swc/crates/swc_ecma_minifier/examples/minifier.rs

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Rust
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#![deny(warnings)]
extern crate swc_node_base;
use std::{env::args, fs, path::Path};
use swc_common::{sync::Lrc, Mark, SourceMap};
use swc_ecma_codegen::text_writer::JsWriter;
use swc_ecma_minifier::{
optimize,
option::{ExtraOptions, MangleOptions, MinifyOptions},
};
use swc_ecma_parser::parse_file_as_module;
use swc_ecma_transforms_base::{fixer::fixer, resolver};
use swc_ecma_visit::FoldWith;
fn main() {
let file = args().nth(1).expect("should provide a path to file");
eprintln!("File: {}", file);
testing::run_test2(false, |cm, handler| {
let fm = cm.load_file(Path::new(&file)).expect("failed to load file");
let unresolved_mark = Mark::new();
let top_level_mark = Mark::new();
let program = parse_file_as_module(
&fm,
Default::default(),
Default::default(),
None,
&mut vec![],
)
.map_err(|err| {
err.into_diagnostic(&handler).emit();
})
.map(|module| module.fold_with(&mut resolver(unresolved_mark, top_level_mark, false)))
.unwrap();
let output = optimize(
program,
cm.clone(),
None,
None,
&MinifyOptions {
compress: Some(Default::default()),
mangle: Some(MangleOptions {
top_level: true,
..Default::default()
}),
..Default::default()
},
&ExtraOptions {
unresolved_mark,
top_level_mark,
},
);
let output = output.fold_with(&mut fixer(None));
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let code = print(cm, &[output], true);
fs::write("output.js", code.as_bytes()).expect("failed to write output");
Ok(())
})
.unwrap();
}
fn print<N: swc_ecma_codegen::Node>(cm: Lrc<SourceMap>, nodes: &[N], minify: bool) -> String {
let mut buf = vec![];
{
let mut emitter = swc_ecma_codegen::Emitter {
cfg: swc_ecma_codegen::Config {
minify,
..Default::default()
},
cm: cm.clone(),
comments: None,
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wr: Box::new(JsWriter::new(cm, "\n", &mut buf, None)),
};
for n in nodes {
n.emit_with(&mut emitter).unwrap();
}
}
String::from_utf8(buf).unwrap()
}