setState函数允许接受两个参数,第一个是partialState,它可以是一个Object,也可以是一个function,也可以是一个空对象指针null,(这里的invariant是一个库,它的用法就是如果不满足第一个参数,则打印后面的错误信息,通常是开发环境中使用),中间部分pass,直接看底部,会发现有两个函数,enqueueSetState和enqueueC
functionadoptClassInstance(workInProgress:Fiber,instance:any):void{instance.updater=classComponentUpdater;workInProgress.stateNode=instance;// The instance needs access to the fiber so that it can schedule updatessetInstance(instance,workInProgress);if(__DEV__){instance._reactInternalInstance=fakeInterna...
functiondispatchSetState(fiber,queue,action){// 帮 react 修复 bug, state 一致的情况下直接 return.constoldState=queue.lastRenderedState;constnewState=action;if(oldState===newState){return;}{if(typeofarguments[3]==='function'){error("State updates from the useState() and useReducer() Hooks do...
In this lesson we'll walk through setting up an updater function that can receive an action argument. We'll also dive into how to separate your state management logic into a separate reducer function much like how Redux operates. It will receive an action which we can add any data and upd...
React.createClass({ displayName: 'Counter', getDefaultProps: function(){ return {initialCount: 0}; }, getInitialState: function() { return {count: this.props.initialCount} }, propTypes: {initialCount: React.PropTypes.number}, tick() { this.setState({count: this.state.count + 1}); },...
ReactUpdateQueue模块,一则作为用户自定义组件ReactComponent的参数updater,供ReactComponent实例的setState、replaceState、forceUpdate方法调用ReactUpdateQueue模块的方法,用于更新state,并重绘组件;一则为用户自定义组件ReactComponent提供isMount方法判断组件是否挂载完成;一则为ReactMount模块使用,在该模块中挂载设定用户自定义组...
1.4.1 state MVC框架常见的状态管理: Backbone: 将View 中与界面交互的状态解耦,一般放到Model中管理 setState : 表现行为就是该组件会尝试重新渲染。 注意点: setState是一个异步的方法。 一个生命周期内所有的setState方法会合并操作。 // 这里认识到了一些新的写法constcurrProps=this.propsletactiveIndex=0if...
function createThunkMiddleware(extraArgument) { return ({ dispatch, getState }) => next => action => { if (typeof action === 'function') { return action(dispatch, getState, extraArgument); } return next(action); }; } const thunk = createThunkMiddleware(); export default thunk; 但是...
Hopes the SetStateAction function can receive a second callback argument, and can used like 'setState' method callback. I have read the official note: // this technically does accept a second argument, but it's already under a deprecation warning // and it's not even released so probably...
functioncreateThunkMiddleware(extraArgument){return({dispatch,getState})=>next=>action=>{if(typeofaction==='function'){returnaction(dispatch,getState,extraArgument);}returnnext(action);}}constthunk=createThunkMiddleware();thunk.withExtraArgument=createThunkMiddleware;exportdefaultthunk; ...