oxc/crates/oxc_minifier/examples/dce.rs

#![allow(clippy::print_stdout)]
use std::path::Path;

use oxc_allocator::Allocator;
use oxc_codegen::{CodeGenerator, CodegenOptions};
use oxc_minifier::{CompressOptions, Compressor};
use oxc_parser::Parser;
use oxc_span::SourceType;
use pico_args::Arguments;

// Instruction:
// create a `test.js`,
// run `cargo run -p oxc_minifier --example dce`

fn main() -> std::io::Result<()> {
    let mut args = Arguments::from_env();

    let nospace = args.contains("--nospace");
    let twice = args.contains("--twice");
    let name = args.free_from_str().unwrap_or_else(|_| "test.js".to_string());

    let path = Path::new(&name);
    let source_text = std::fs::read_to_string(path)?;
    let source_type = SourceType::from_path(path).unwrap();

    let mut allocator = Allocator::default();
    let printed = dce(&allocator, &source_text, source_type, nospace);
    println!("{printed}");

    if twice {
        allocator.reset();
        let printed2 = dce(&allocator, &printed, source_type, nospace);
        println!("{printed2}");
        println!("same = {}", printed == printed2);
    }

    Ok(())
}

fn dce(allocator: &Allocator, source_text: &str, source_type: SourceType, nospace: bool) -> String {
    let ret = Parser::new(allocator, source_text, source_type).parse();
    let mut program = ret.program;
    Compressor::new(allocator, CompressOptions::default()).dead_code_elimination(&mut program);
    CodeGenerator::new()
        .with_options(CodegenOptions { minify: nospace, ..CodegenOptions::default() })
        .build(&program)
        .code
}