Rollup library script - JavaScript API

rollup.js

/* eslint-env node */
const fs = require('fs');
const uglifyJs = require('uglify-js');
const chalk = require('chalk');
const maxmin = require('maxmin');

const rollup = require('rollup');
const babelrc = require('babelrc-rollup').default;
const babel = require('rollup-plugin-babel');
const nodeResolve = require('rollup-plugin-node-resolve');
const commonjs = require('rollup-plugin-commonjs');
const postcss = require('rollup-plugin-postcss');
const replace = require('rollup-plugin-replace');

const pkg = require('./package.json');

const filename = 'pict';
const moduleName = 'Pict';
const name = `${pkg.name} v${pkg.version}`;
const copyright = `(c) ${new Date().getFullYear()}`;
const url = `https://github.com/${pkg.repository}`;
const banner = `/*! ${name} | ${copyright} | ${pkg.license} License | ${url} */`;

const watch = process.argv.indexOf('--watch') !== -1;

let cache = null;
let building = false;
let needsRebuild = false;

const generateBundle = async () => {
  if (building) {
    needsRebuild = true;
    return;
  }

  building = true;
  needsRebuild = false;

  if (watch) {
    console.log(new Date().toString());
  }

  try {

    const bundle = await rollup.rollup({
      cache,
      entry: `src/js/${filename}.js`,
      plugins: [
        postcss({
          plugins: [
            require('postcss-import')(),
            require('postcss-units')({
              size: 16
            }),
            require('postcss-cssnext')({
              warnForDuplicates: false
            })
          ],
          extensions: [ '.css' ]
        }),
        babel(babelrc()),
        nodeResolve({
          jsnext: true
        }),
        commonjs(),
        replace({
          'process.env.NODE_ENV': JSON.stringify( 'production' )
        })
      ]
    });

    cache = bundle;

    const { code, map } = await bundle.generate({
      format: 'umd',
      moduleName: moduleName,
      sourceMap: true,
      sourceMapFile: `dist/${filename}.js.map`,
      banner
    });

    fs.writeFileSync(`dist/${filename}.js`, `${code}\n//# sourceMappingURL=${filename}.js.map`);
    fs.writeFileSync(`dist/${filename}.js.map`, map.toString());

    const size = maxmin(code, code, true).replace(/^(.*? → )/, '');
    console.log(`Created bundle ${chalk.cyan(`${filename}.js`)}: ${size}`);

    const minified = uglifyJs.minify(code, {
      sourceMap: {
        content: map,
        url: `dist/${filename}.min.js.map`,
      },
      output: {
        preamble: banner
      },
      mangle: {
        reserved: [moduleName]
      }
    });

    fs.writeFileSync(`dist/${filename}.min.js`, minified.code.replace(/\/\/# sourceMappingURL=\S+/, ''));
    fs.writeFileSync(`dist/${filename}.min.js.map`, minified.map);

    const minifiedSize = maxmin(code, minified.code, true);
    console.log(`Created bundle ${chalk.cyan(`${filename}.min.js`)}: ${minifiedSize}`);

    building = false;

    if (needsRebuild) {
      generateBundle();
    }

  } catch (error) {
    console.log(error);
  }
};

generateBundle();

if (watch) {
  const chokidar = require('chokidar');
  const watcher = chokidar.watch('src/**/*');
  watcher.on('change', generateBundle);
}