vuex/docs/en/api.md

API Reference

Vuex.Store

import Vuex from 'vuex'

const store = new Vuex.Store({ ...options })

Vuex.Store Constructor Options

• state

  • type: Object | Function

  The root state object for the Vuex store. Details

  If you pass a function that returns an object, the returned object is used as the root state. This is useful when you want to reuse the state object especially for module reuse. Details

• mutations

  • type: { [type: string]: Function }

  Register mutations on the store. The handler function always receives state as the first argument (will be module local state if defined in a module), and receives a second payload argument if there is one.

  Details

• actions

  • type: { [type: string]: Function }

  Register actions on the store. The handler function receives a context object that exposes the following properties:

  {
    state,     // same as store.state, or local state if in modules
    rootState, // same as store.state, only in modules
    commit,    // same as store.commit
    dispatch,  // same as store.dispatch
    getters    // same as store.getters
  }
  

  Details

• getters

  • type: { [key: string]: Function }

  Register getters on the store. The getter function receives the following arguments:

  state,     // will be module local state if defined in a module.
  getters    // same as store.getters
  

  Specific when defined in a module

  state,       // will be module local state if defined in a module.
  getters,     // module local getters of the current module
  rootState,   // global state
  rootGetters  // all getters
  

  Registered getters are exposed on store.getters.

  Details

• modules

  • type: Object

  An object containing sub modules to be merged into the store, in the shape of:

  {
    key: {
      state,
      namespaced?,
      mutations?,
      actions?,
      getters?,
      modules?
    },
    ...
  }
  

  Each module can contain state and mutations similar to the root options. A module's state will be attached to the store's root state using the module's key. A module's mutations and getters will only receives the module's local state as the first argument instead of the root state, and module actions' context.state will also point to the local state.

  Details

• plugins

  • type: Array<Function>

  An array of plugin functions to be applied to the store. The plugin simply receives the store as the only argument and can either listen to mutations (for outbound data persistence, logging, or debugging) or dispatch mutations (for inbound data e.g. websockets or observables).

  Details

• strict

  • type: Boolean
  • default: false

  Force the Vuex store into strict mode. In strict mode any mutations to Vuex state outside of mutation handlers will throw an Error.

  Details

Vuex.Store Instance Properties

• state

  • type: Object

  The root state. Read only.

• getters

  • type: Object

  Exposes registered getters. Read only.

Vuex.Store Instance Methods

• commit(type: string, payload?: any, options?: Object) | commit(mutation: Object, options?: Object)

Commit a mutation. options can have root: true that allows to commit root mutations in namespaced modules. Details

• dispatch(type: string, payload?: any, options?: Object) | dispatch(action: Object, options?: Object)

Dispatch an action. options can have root: true that allows to dispatch root actions in namespaced modules. Returns a Promise that resolves all triggered action handlers. Details

• replaceState(state: Object)

Replace the store's root state. Use this only for state hydration / time-travel purposes.

• watch(getter: Function, cb: Function, options?: Object)

Reactively watch a getter function's return value, and call the callback when the value changes. The getter receives the store's state as the only argument. Accepts an optional options object that takes the same options as Vue's vm.$watch method.

To stop watching, call the returned handle function.

• subscribe(handler: Function)

Subscribe to store mutations. The handler is called after every mutation and receives the mutation descriptor and post-mutation state as arguments:

  store.subscribe((mutation, state) => {
    console.log(mutation.type)
    console.log(mutation.payload)
  })

Most commonly used in plugins. Details

• subscribeAction(handler: Function)

New in 2.5.0

Subscribe to store actions. The handler is called for every dispatched action and receives the action descriptor and current store state as arguments:

  store.subscribeAction((action, state) => {
    console.log(action.type)
    console.log(action.payload)
  })

Most commonly used in plugins. Details

• registerModule(path: string | Array<string>, module: Module, options?: Object)

Register a dynamic module. Details

options can have preserveState: true that allows to preserve the previous state. Useful with Server Side Rendering.

• unregisterModule(path: string | Array<string>)

Unregister a dynamic module. Details

• hotUpdate(newOptions: Object)

Hot swap new actions and mutations. Details

Component Binding Helpers

• mapState(namespace?: string, map: Array<string> | Object): Object

Create component computed options that return the sub tree of the Vuex store. Details

The first argument can optionally be a namespace string. Details

• mapGetters(namespace?: string, map: Array<string> | Object): Object

Create component computed options that return the evaluated value of a getter. Details

The first argument can optionally be a namespace string. Details

• mapActions(namespace?: string, map: Array<string> | Object): Object

Create component methods options that dispatch an action. Details

The first argument can optionally be a namespace string. Details

• mapMutations(namespace?: string, map: Array<string> | Object): Object

Create component methods options that commit a mutation. Details

The first argument can optionally be a namespace string. Details

• createNamespacedHelpers(namespace: string): Object

Create namespaced component binding helpers. The returned object contains mapState, mapGetters, mapActions and mapMutations that are bound with the given namespace. Details