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Mtillmann/mterser.js

Created December 22, 2021 14:45
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  1. Mtillmann created this gist Dec 22, 2021.
    105 changes: 105 additions & 0 deletions mterser.js
    View file
    Original file line number Diff line number Diff line change
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    /**
    * minify all files matched by given glob pattern through terser. Requires `glob` to be installed:
    *
    * npm i glob --save-dev
    *
    * Place the scripts in your projects scripts folder, then add it to your package.json's scripts like this
    *
    * "mterser": "node scripts/mterser.js --glob dist/umd/*.js --compress --mangle --comments false",
    *
    * and run it by calling `npm run mterser`. A `terser` npm script should also be available, see `--terser-cmd` below.
    *
    * Options
    *
    * --glob required glob pattern to match source files
    * --terser-cmd optional defaults to `npm run terser`. The npm script should exist and simple call "terser".
    * --dryrun optional Will only display the terser commands that are generated
    * --outdir optional When given, this is the folder that the generated files are placed in
    *
    * By default the minified filenames have `.min` inserted before the final `.js` extension. To change that behaviour,
    * modify the minifiedFilename and isFileMinified functions below.
    *
    */

    let terserOptions = [],
    globPattern,
    outDir = null,
    dryRun = false,
    terserCommand = 'npm run terser';


    const glob = require('glob'),
    {exec} = require('child_process'),
    terserOptionShortCuts = {
    "-V": "--version",
    "-p": "--parse",
    "-c": "--compress",
    "-m": "--mangle",
    "-f": "--format",
    "-o": "--output",
    "-d": "--define",
    "-e": "--enclose"
    },
    expandOptionName = option => option in terserOptionShortCuts ? terserOptionShortCuts[option] : option,
    isOption = string => string.slice(0, 2) === '--',
    type = string => /^true|false$/.test(string) ? string === 'true' : /^\d+$/.test(string) ? parseInt(string, 10) : string,
    minifiedFilename = filename => filename.replace(/\.js$/, '.min.js'),
    isFileMinified = filename => /\.min\.js$/.test(filename),
    args = process.argv.slice(2),
    terminator = '_____END_____';
    args.push(terminator);

    args.reduce((previous, current) => {
    if (previous && isOption(expandOptionName(previous))) {
    const option = expandOptionName(previous);

    if (option === '--glob') {
    globPattern = current;
    } else if (option === '--outdir') {
    outDir = current;
    } else if (option === '--terser-cmd') {
    terserCommand = current;
    } else if (option === '--dryrun') {
    dryRun = true;
    } else {
    terserOptions.push(previous);
    if (!isOption(expandOptionName(current)) && current !== terminator) {
    terserOptions.push(type(current));
    }
    }
    }
    return current;
    }, null);

    if (dryRun) {
    console.log('DRY RUN:');
    }

    glob(globPattern, {}, (error, files) => {
    if (error) {
    return console.log(`glob error : ${error}`);
    }
    files.forEach(file => {
    let input = file,
    output = minifiedFilename(file),
    options = [...terserOptions];
    if (outDir) {
    output = (outDir + '/' + output.split('/').pop()).replace(/\/{2,}/g, '/');
    }
    if (isFileMinified(file)) {
    return console.log(`skipping: ${file}`);
    }
    options.unshift(input);
    options.unshift('--');
    options.unshift(terserCommand);
    options.push('--output');
    options.push(output);
    if (dryRun) {
    return console.log(options.join(' '));
    }
    exec(options.join(' '));
    });
    });