getter

遍历注册getter

module.forEachGetter((getter, key) => {
  const namespacedType = namespace + key
  registerGetter(store, namespacedType, getter, local)
})

注册getter

// 把所有的getters存储在_wrappedGetters上
function registerGetter (store, type, rawGetter, local) {
  if (store._wrappedGetters[type]) {
    if (__DEV__) {
      console.error(`[vuex] duplicate getter key: ${type}`)
    }
    return
  }
  // 这里的rawGetter就是我们的原始
  store._wrappedGetters[type] = function wrappedGetter (store) {
    return rawGetter(
      local.state, // local state
      local.getters, // local getters
      store.state, // root state
      store.getters // root getters
    )
  }
}

  const wrappedGetters = store._wrappedGetters
  const computed = {}
  forEachValue(wrappedGetters, (fn, key) => {
    // use computed to leverage its lazy-caching mechanism
    // direct inline function use will lead to closure preserving oldVm.
    // using partial to return function with only arguments preserved in closure environment.
    computed[key] = partial(fn, store)
    // 按照路径定义了store.getters
    Object.defineProperty(store.getters, key, {
      get: () => store._vm[key],
      enumerable: true // for local getters
    })
  })
  store._vm = new Vue({
    data: {
      $$state: state
    },
    computed
  })

function makeLocalGetters (store, namespace) {
  if (!store._makeLocalGettersCache[namespace]) {
    const gettersProxy = {}
    const splitPos = namespace.length
    Object.keys(store.getters).forEach(type => {
      // skip if the target getter is not match this namespace
      if (type.slice(0, splitPos) !== namespace) return

      // extract local getter type
      const localType = type.slice(splitPos)

      // Add a port to the getters proxy.
      // Define as getter property because
      // we do not want to evaluate the getters in this time.
      Object.defineProperty(gettersProxy, localType, {
        get: () => store.getters[type],
        enumerable: true
      })
    })
    store._makeLocalGettersCache[namespace] = gettersProxy
  }

  return store._makeLocalGettersCache[namespace]
}