metro-minify-terser/src/minifier.js

🚇 Alternative minifier for Metro

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 *  strict-local
 * @format
 */

'use strict';

const terser = require('terser');








function minifier(
code,
sourceMap,
filename)

{let options = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : {};
  const result = minify(code, sourceMap, options);

  if (!sourceMap) {
    return { code: result.code };
  }

  const map = JSON.parse(result.map);
  map.sources = [filename];

  return { code: result.code, map };
}

function minify(
inputCode,
inputMap,
options)
{
  const result = terser.minify(inputCode, {
    mangle: {
      toplevel: false,
      reserved: options.reserved },

    output: {
      ascii_only: true,
      quote_style: 3,
      wrap_iife: true },

    sourceMap: {
      content: inputMap,
      includeSources: false },

    toplevel: false,
    compress: {
      // reduce_funcs inlines single-use function, which cause perf regressions.
      reduce_funcs: false } });



  if (result.error) {
    throw result.error;
  }

  return {
    code: result.code,
    map: result.map };

}

const metroMinifier = minifier;

module.exports = metroMinifier;