Improved looping; simplify assign

Author: crazy4groovy

README.md

@@ -69,10 +69,10 @@ You can find the library on `window.unistore`.
 import createStore from 'unistore'
 import { Provider, connect } from 'unistore/preact'
 
-let store = createStore({ count: 0 })
+const store = createStore({ count: 0 })
 
 // If actions is a function, it gets passed the store:
-let actions = store => ({
+const actions = store => ({
   // Actions can just return a state update:
   increment(state) {
     return { count: state.count+1 }
@@ -90,7 +90,7 @@ let actions = store => ({
 
   // Async actions can be pure async/promise functions:
   async getStuff(state) {
-    let res = await fetch('/foo.json')
+    const res = await fetch('/foo.json')
     return { stuff: await res.json() }
   },
 
@@ -126,8 +126,8 @@ Make sure to have [Redux devtools extension](https://github.com/zalmoxisus/redux
 import createStore from 'unistore'
 import devtools    from 'unistore/devtools'
 
-let initialState = { count: 0 };
-let store = process.env.NODE_ENV === 'production' ?  createStore(initialState) : devtools(createStore(initialState));
+const initialState = { count: 0 };
+const store = process.env.NODE_ENV === 'production' ?  createStore(initialState) : devtools(createStore(initialState));
 
 // ...
 ```

src/index.js

@@ -15,22 +15,14 @@ export default function createStore(state) {
 	state = state || {};
 
 	function unsubscribe(listener) {
-		let out = [];
-		for (let i=0; i<listeners.length; i++) {
-			if (listeners[i]===listener) {
-				listener = null;
-			}
-			else {
-				out.push(listeners[i]);
-			}
-		}
-		listeners = out;
+		let i = listeners.indexOf(listener);
+		if (i > -1) listeners.splice(i, 1);
 	}
 
 	function setState(update, overwrite, action) {
-		state = overwrite ? update : assign(assign({}, state), update);
-		let currentListeners = listeners;
-		for (let i=0; i<currentListeners.length; i++) currentListeners[i](state, action);
+		state = overwrite ? update : assign({}, state, update);
+		let i = listeners.length;
+		while (i-- > 0) listeners[i](state, action);
 	}
 
 	/** An observable state container, returned from {@link createStore}
@@ -52,8 +44,10 @@ export default function createStore(state) {
 
 			// Note: perf tests verifying this implementation: https://esbench.com/bench/5a295e6299634800a0349500
 			return function() {
-				let args = [state];
-				for (let i=0; i<arguments.length; i++) args.push(arguments[i]);
+				let args = [];
+				let i = arguments.length;
+				while (i-- > 0) args.shift(arguments[i]);
+				args.shift(state);
 				let ret = action.apply(this, args);
 				if (ret!=null) {
 					if (ret.then) ret.then(apply);

src/integrations/preact.js

@@ -40,7 +40,7 @@ export function connect(mapStateToProps, actions) {
 			this.componentWillUnmount = () => {
 				store.unsubscribe(update);
 			};
-			this.render = props => h(Child, assign(assign(assign({}, boundActions), props), state));
+			this.render = props => h(Child, assign({}, boundActions, props, state));
 		}
 		return (Wrapper.prototype = new Component()).constructor = Wrapper;
 	};

src/integrations/react.js

@@ -46,7 +46,7 @@ export function connect(mapStateToProps, actions) {
 			this.componentWillUnmount = () => {
 				store.unsubscribe(update);
 			};
-			this.render = () => createElement(Child, assign(assign(assign({}, boundActions), this.props), state));
+			this.render = () => createElement(Child, assign({}, boundActions, this.props, state));
 		}
 		Wrapper.contextTypes = CONTEXT_TYPES;
 		return (Wrapper.prototype = Object.create(Component)).constructor = Wrapper;

src/util.js

@@ -2,9 +2,7 @@
 export function mapActions(actions, store) {
 	if (typeof actions==='function') actions = actions(store);
 	let mapped = {};
-	for (let i in actions) {
-		mapped[i] = store.action(actions[i]);
-	}
+	for (let i in actions) mapped[i] = store.action(actions[i]);
 	return mapped;
 }
 
@@ -14,16 +12,18 @@ export function select(properties) {
 	if (typeof properties==='string') properties = properties.split(/\s*,\s*/);
 	return state => {
 		let selected = {};
-		for (let i=0; i<properties.length; i++) {
-			selected[properties[i]] = state[properties[i]];
-		}
+		let i = properties.length;
+		while (i-- > 0) selected[properties[i]] = state[properties[i]];
 		return selected;
 	};
 }
 
 
-// Lighter Object.assign stand-in
-export function assign(obj, props) {
-	for (let i in props) obj[i] = props[i];
-	return obj;
+// Lighter Object.assign clone
+export function assign(_) {
+	for (let i = 1; i<arguments.length; i++)
+		for (let j in arguments[i])
+			arguments[0][j] = arguments[i][j];
+
+	return arguments[0];
 }