Created
July 13, 2017 11:34
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Understand Redux in 5 minutes
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| export class Store { | |
| constructor(executor, initialState = {}) { | |
| this.subscribers = []; | |
| this.state = initialState; | |
| // function that executes reducer or combined reducers and returns the new state | |
| this.executor = executor; | |
| } | |
| notifySubscribers() { | |
| for (let i = 0; i < this.subscribers.length; i++) { | |
| this.subscribers[i](); | |
| } | |
| } | |
| getState() { | |
| return this.state; | |
| } | |
| dispatch(actionResult) { | |
| this.state = this.executor(this.state, actionResult); | |
| this.notifySubscribers(); | |
| } | |
| subscribe(fn) { | |
| this.subscribers.push(fn); | |
| } | |
| } | |
| export function createStore(reducerOrCombinedReducers, initialState) { | |
| return new Store((state, actionResult) => { | |
| // returns the new state with reducer function or combined reducer function | |
| return reducerOrCombinedReducers(state, actionResult); | |
| }, initialState); | |
| } | |
| export function combineReducers(reducerObject) { | |
| // returns a function that executes all reducers | |
| return (state, actionResult) => { | |
| // executes all reducers and return the new state | |
| let newState = {}; | |
| for (let type in reducerObject) { | |
| if (reducerObject.hasOwnProperty(type)) { | |
| let reducer = reducerObject[type]; | |
| newState[type] = reducer(state[type], actionResult); | |
| } | |
| } | |
| return newState; | |
| }; | |
| } |
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