swc/crates/swc_webpack_ast/scripts/bench.js

const Benchmark = require('benchmark');
const acorn = require("acorn");
const jsx = require("acorn-jsx");
const parser = acorn.Parser.extend(jsx());


const fs = require('fs');
const path = require('path');


const src = fs.readFileSync(path.join(process.argv[2], "input.js"), 'utf8');
const jsonStr = fs.readFileSync(path.join(process.argv[2], "output.json"), 'utf8');


{
    parser.parse(src, {
        ecmaVersion: 2020,
        ranges: true,
        allowHashBang: true,
        sourceType: 'module'
    })
}
const suite = new Benchmark.Suite;

suite
    .add('acorn', () => {
        parser.parse(src, {
            ecmaVersion: 2020,
            ranges: true,
            allowHashBang: true,
            sourceType: 'module'
        })
    })
    .add({
        name: 'acorn-real',
        fn: (deferred) => {
            fs.promises.readFile(path.join(process.argv[2], "input.js"), 'utf8')
                .then((src) => {
                    parser.parse(src, {
                        ecmaVersion: 2020,
                        ranges: true,
                        allowHashBang: true,
                        sourceType: 'module'
                    });
                    deferred.resolve()
                })
        },
        defer: true,
        async: true,
        queued: true
    })
    .add('json', () => {
        JSON.parse(jsonStr)
    })
    .on('cycle', function (event) {
        console.log(String(event.target));
    })
    .on('complete', function () {
        console.log('Fastest is ' + this.filter('fastest').map('name'));
    })
    .run({
        async: true
    })