rollem/src/index.js

Roll up multiple ES6 bundles at once

'use strict'

const debug = require('debug')('rollem')
const rollup = require('rollup')
const R = require('ramda')

const {
  mergeFolders,
  globifyFolders
} = require('./merge-folders')

function buildBundle (config) {
  return rollup.rollup(config)
    .then(function (bundle) {
      return bundle.write({
        format: config.format || 'es',
        dest: config.dest,
        globals: config.globals,
        moduleName: config.moduleName,
        sourceMap: config.sourceMap,
        interop: config.interop,
        banner: config.banner
      }).then(() => config.dest)
    })
}

function buildBundles (configs) {
  const promises = configs.map(buildBundle)
  return Promise.all(promises)
    .then((bundles) => {
      console.log('[%s] built %d bundles', new Date().toTimeString(), configs.length)
      debug(bundles)
      return bundles
    })
    .catch((err) => {
      console.error(err.stack)
    })
}

function collectInputFolders (configs) {
  const filenames = R.map(R.prop('entry'), configs)
  return globifyFolders(mergeFolders(filenames))
}

function rollem (configs, options) {
  options = options || {}
  debug('Rollem configs')
  debug(configs)
  debug('Rollem options', options)

  console.assert(Array.isArray(configs), 'expected list of configs')

  if (options.watch) {
    const folders = collectInputFolders(configs)
    console.log('[%s] watching source folders for changes', new Date().toTimeString(), folders)

    const gaze = require('gaze')
    const EventEmitter = require('events')
    const watcher = new EventEmitter()

    gaze(folders, (err, gazeWatcher) => {
      if (err) {
        watcher.emit('failed', err)
      } else {
        gazeWatcher.on('all', (_event, filepath) => {
          watcher.emit('changed', filepath)
          buildBundles(configs).then((files) => watcher.emit('rolled', files))
        })
      }
    })

    buildBundles(configs).then((files) => watcher.emit('rolled', files))
    return Promise.resolve(watcher)
  } else {
    return buildBundles(configs)
  }
}

module.exports = rollem