const {mutations, state, getters} = option
    let changeGetters = {}
    // getters实现
    Object.keys(getters).forEach(key => {
        changeGetters[key] = () => getters[key](this._vm._data.$$data)
    })
    this._vm = new Vue({
        data() {
            return {
                $$data: state
            }
        },
        computed: changeGetters
    })
    this._mutations = mutations
试了一下，能用。

老师，您好，大概过了下vuex的源码。有个地方不是很理解，为什么vuex内部存放mutations、actions 都要以数组的形式存放呢。每个模块中存在的 mutations 下的操作应该是唯一的才对啊，即使是不同模块下的同名的mutation 它们type值也不一样，真的想不明请老师为我解惑。
源码：
function registerMutation (store, type, handler, local) {
  const entry = store._mutations[type] || (store._mutations[type] = [])
  entry.push(function wrappedMutationHandler (payload) {
    handler.call(store, local.state, payload)
  })
}
为什么不直接这样写：
function registerMutation (store, type, handler, local) {
  store._mutations[type] = function (payload) {
    handler.call(store, local.state, payload)
  }
}