oxc/tasks/minsize/src/lib.rs

use std::{
    fs::File,
    io::{self, Write},
};

use flate2::{write::GzEncoder, Compression};
use humansize::{format_size, DECIMAL};

use oxc_allocator::Allocator;
use oxc_codegen::{Codegen, CodegenOptions};
use oxc_minifier::{CompressOptions, Minifier, MinifierOptions};
use oxc_parser::Parser;
use oxc_span::SourceType;
use oxc_tasks_common::{project_root, TestFile, TestFiles};

// #[test]
// #[cfg(any(coverage, coverage_nightly))]
// fn test() {
// run().unwrap();
// }

/// # Panics
/// # Errors
pub fn run() -> Result<(), io::Error> {
    let files = TestFiles::new();

    let path = project_root().join("tasks/minsize/minsize.snap");

    let mut out = String::new();
    out.push_str(&format!(
        "{:width$} -> {:width$} -> {:width$}\n",
        "Original",
        "Minified",
        "Gzip",
        width = 10
    ));

    for file in files.files() {
        let minified = minify_twice(file);
        let s = format!(
            "{:width$} -> {:width$} -> {:width$} {:width$}\n\n",
            format_size(file.source_text.len(), DECIMAL),
            format_size(minified.len(), DECIMAL),
            format_size(gzip_size(&minified), DECIMAL),
            &file.file_name,
            width = 10
        );
        out.push_str(&s);
    }

    println!("{out}");

    let mut snapshot = File::create(path)?;
    snapshot.write_all(out.as_bytes())?;
    snapshot.flush()?;
    Ok(())
}

fn minify_twice(file: &TestFile) -> String {
    let source_type = SourceType::from_path(&file.file_name).unwrap();
    let options = MinifierOptions {
        compress: CompressOptions { evaluate: false, ..CompressOptions::default() },
        ..MinifierOptions::default()
    };
    let source_text1 = minify(&file.source_text, source_type, options);
    let source_text2 = minify(&source_text1, source_type, options);
    assert!(source_text1 == source_text2, "Minification failed for {}", &file.file_name);
    source_text2
}

fn minify(source_text: &str, source_type: SourceType, options: MinifierOptions) -> String {
    let allocator = Allocator::default();
    let ret = Parser::new(&allocator, source_text, source_type).parse();
    let program = allocator.alloc(ret.program);
    Minifier::new(options).build(&allocator, program);
    Codegen::<true>::new("", source_text, ret.trivias, CodegenOptions::default())
        .build(program)
        .source_text
}

fn gzip_size(s: &str) -> usize {
    let mut e = GzEncoder::new(Vec::new(), Compression::best());
    e.write_all(s.as_bytes()).unwrap();
    let s = e.finish().unwrap();
    s.len()
}