Function mergeAssets

m3u8/vue.js:1315–1328

* Assets * * When a vm is present (instance creation), we need to do * a three-way merge between constructor options, instance * options and parent options.

(
    parentVal,
    childVal,
    vm,
    key
  )

   * options and parent options.
   */
  function mergeAssets (
    parentVal,
    childVal,
    vm,
    key
  ) {
    var res = Object.create(parentVal || null);
    if (childVal) {
      assertObjectType(key, childVal, vm);
      return extend(res, childVal)
    } else {
      return res
    }
  }

  ASSET_TYPES.forEach(function (type) {
    strats[type + 's'] = mergeAssets;