text: /* @flow */
  
  import { ASSET_TYPES } from 'shared/constants'
  import { isPlainObject, validateComponentName } from '../util/index'
  
  export function initAssetRegisters (Vue: GlobalAPI) {
    /**
     * Create asset registration methods.
     *
     * 有 ASSET_TYPES = ['component','directive','filter'];
     */
    ASSET_TYPES.forEach(type => {
      Vue[type] = function (
        id: string,
        definition: Function | Object
      ): Function | Object | void {
        if (!definition) {
          return this.options[type + 's'][id]
        } else {
          /* istanbul ignore if */
          if (process.env.NODE_ENV !== 'production' && type === 'component') {
            validateComponentName(id)
          }
          if (type === 'component' && isPlainObject(definition)) {
            definition.name = definition.name || id
            definition = this.options._base.extend(definition)
          }
          if (type === 'directive' && typeof definition === 'function') {
            definition = { bind: definition, update: definition }
          }
          this.options[type + 's'][id] = definition
          return definition
        }
      }
    })
  }
  