tt-mp/core/helpers/relationsBehavior.js

一套组件化、可复用、易扩展的头条小程序 UI 组件库

import isEmpty from './isEmpty'
import debounce from './debounce'

/**
 * bind func to obj
 */
function bindFunc(obj, method, observer) {
  const oldFn = obj[method]
  obj[method] = function (target) {
    if (observer) {
      observer.call(this, target, {
        [method]: true,
      })
    }
    if (oldFn) {
      oldFn.call(this, target)
    }
  }
}

// default methods
const methods = ['linked', 'linkChanged', 'unlinked']

// extra props
const extProps = ['observer']

export default Behavior({
  lifetimes: {
    created() {
      this._debounce = null
    },
    detached() {
      if (this._debounce && this._debounce.cancel) {
        this._debounce.cancel()
      }
    },
  },
  definitionFilter(defFields) {
    const { relations } = defFields

    if (!isEmpty(relations)) {
      for (const key in relations) {
        const relation = relations[key]

        // bind func
        methods.forEach((method) =>
          bindFunc(relation, method, relation.observer)
        )

        // delete extProps
        extProps.forEach((prop) => delete relation[prop])
      }
    }

    Object.assign((defFields.methods = defFields.methods || {}), {
      getRelationsName: function (
        types = ['parent', 'child', 'ancestor', 'descendant']
      ) {
        return Object.keys(relations || {})
          .map((key) => {
            if (relations[key] && types.includes(relations[key].type)) {
              return key
            }
            return null
          })
          .filter((v) => !!v)
      },
      debounce: function (func, wait = 0, immediate = false) {
        return (this._debounce =
          this._debounce || debounce(func.bind(this), wait, immediate)).call(
          this
        )
      },
    })
  },
})