Proposal: Global action enhancers - WIP

src/store.js

@@ -1,7 +1,7 @@
 import applyMixin from './mixin'
 import devtoolPlugin from './plugins/devtool'
 import ModuleCollection from './module/module-collection'
-import { forEachValue, isObject, isPromise, assert } from './util'
+import { compose, forEachValue, isObject, isPromise, assert } from './util'
 
 let Vue // bind on install
 
@@ -21,6 +21,7 @@ export class Store {
     }
 
     const {
+      actionEnhancers = [],
       plugins = [],
       strict = false
     } = options
@@ -42,9 +43,14 @@ export class Store {
     this._subscribers = []
     this._watcherVM = new Vue()
 
-    // bind commit and dispatch to self
     const store = this
-    const { dispatch, commit } = this
+    const { commit } = this
+    let { dispatch } = this
+
+    const actionEnhancerChain = getActionEnhancerChain(store, state, actionEnhancers)
+    dispatch = compose(...actionEnhancerChain)(dispatch.bind(store))
+
+    // bind commit and dispatch to self
     this.dispatch = function boundDispatch (type, payload) {
       return dispatch.call(store, type, payload)
     }
@@ -438,6 +444,15 @@ function enableStrictMode (store) {
   }, { deep: true, sync: true })
 }
 
+function getActionEnhancerChain (store, state, actionEnhancers) {
+  return actionEnhancers.map(actionEnhancer => actionEnhancer({
+    dispatch: store.dispatch,
+    commit: store.commit,
+    getters: store.getters,
+    state
+  }))
+}
+
 function getNestedState (state, path) {
   return path.length
     ? path.reduce((state, key) => state[key], state)

src/util.js

@@ -64,3 +64,26 @@ export function isPromise (val) {
 export function assert (condition, msg) {
   if (!condition) throw new Error(`[vuex] ${msg}`)
 }
+
+/**
+ * Taken from Redux repo
+ * Composes single-argument functions from right to left. The rightmost
+ * function can take multiple arguments as it provides the signature for
+ * the resulting composite function.
+ *
+ * @param {...Function} funcs The functions to compose.
+ * @returns {Function} A function obtained by composing the argument functions
+ * from right to left. For example, compose(f, g, h) is identical to doing
+ * (...args) => f(g(h(...args))).
+ */
+export function compose (...funcs) {
+  if (funcs.length === 0) {
+    return arg => arg
+  }
+
+  if (funcs.length === 1) {
+    return funcs[0]
+  }
+
+  return funcs.reduce((a, b) => (...args) => a(b(...args)))
+}