@mpxjs/webpack-plugin/lib/utils/make-map.js

mpx compile core

/**
 * Make a map and return a function for checking if a key
 * is in that map.
 */
module.exports = function makeMap (str, expectsLowerCase) {
  const map = Object.create(null)
  const list = str.split(',')
  for (let i = 0; i < list.length; i++) {
    map[list[i].trim()] = true
  }
  return expectsLowerCase ? val => !!map[val.toLowerCase()] : val => !!map[val]
}