mutation和commit

遍历注册mutation

module.forEachMutation((mutation, key) => {
    const namespacedType = namespace + key
    registerMutation(store, namespacedType, mutation, local)
 })

推入_mutation队列里

function registerMutation (store, type, handler, local) {
  const entry = store._mutations[type] || (store._mutations[type] = [])
  entry.push(function wrappedMutationHandler (payload) {
    // 这里的state就是当前store的state
    handler.call(store, local.state, payload)
  })
}

commit 方法

commit (_type, _payload, _options) {
  // check object-style commit
  const {
    type,
    payload,
    options
  } = unifyObjectStyle(_type, _payload, _options)

  const mutation = { type, payload }
  // 这里的this就是store
  const entry = this._mutations[type]
  if (!entry) {
    if (__DEV__) {
      console.error(`[vuex] unknown mutation type: ${type}`)
    }
    return
  }
  // 执行mutation相应定义的方法
  this._withCommit(() => {
    entry.forEach(function commitIterator (handler) {
      handler(payload)
    })
  })

  // 执行订阅的事件
  this._subscribers
    .slice() // shallow copy to prevent iterator invalidation if subscriber synchronously calls unsubscribe
    .forEach(sub => sub(mutation, this.state))

  if (
    __DEV__ &&
    options && options.silent
  ) {
    console.warn(
      `[vuex] mutation type: ${type}. Silent option has been removed. ` +
      'Use the filter functionality in the vue-devtools'
    )
  }
}

_withCommit (fn) {
  const committing = this._committing
  this._committing = true
  fn()
  this._committing = committing
}

// 这里是兼容commit的对象风格式的提交
/*
  store.commit('increment', {
    amount: 10
  })
  store.commit({
    type: 'increment',
    amount: 10
  })
*/
function unifyObjectStyle (type, payload, options) {
  if (isObject(type) && type.type) {
    options = payload
    payload = type
    type = type.type
  }

  if (__DEV__) {
    assert(typeof type === 'string', `expects string as the type, but found ${typeof type}.`)
  }

  return { type, payload, options }
}