✨ utils functions

- compose
- applyMiddleware

lib/applyMiddleware.js

@@ -1 +1,26 @@
-// TODO
+import compose from './compose'
+
+/**
+ * applyMiddleware is a function produce(return) enhancer function
+ * middleware only can extend the dispatch
+ * @param  {...any} middlewares
+ */
+export default (...middlewares) => {
+  return createStore =>
+    (...args) => {
+      const store = createStore(...args)
+
+      const middlewareAPI = {
+        getState: store.getState
+        // dispatch: (...args) => dispatch(args)
+      }
+
+      const chain = middlewares.map(middleware => middleware(middlewareAPI))
+      const dispatch = compose(...chain)(store.dispatch)
+
+      return {
+        ...store,
+        dispatch
+      }
+    }
+}

lib/compose.js

@@ -0,0 +1,15 @@
+/**
+ *
+ * @param  {...any} funcs
+ * @returns
+ */
+export default (...funcs) => {
+  if (funcs.length === 0) return arg => arg
+  if (funcs.length === 1) return funcs[0]
+
+  return funcs.reduce(
+    (a, b) =>
+      (...args) =>
+        a(b(...args))
+  )
+}

lib/createStore.js

@@ -1,7 +1,7 @@
 // @ts-check
 
 // @ts-ignore
-import { isPlainObject, ActionTypes, error } from 'utils'
+import { isPlainObject, ActionTypes, error } from './utils'
 
 // TODO subscribe while dispatch something...
 

lib/main.js

@@ -0,0 +1,5 @@
+import { createStore } from './createStore'
+import compose from './compose'
+import applyMiddleware from './applyMiddleware'
+
+export { createStore, compose, applyMiddleware }