componentWillReceiveProps:function(nextProps) {this.setState({likesIncreasing: nextProps.likeCount>this.props.likeCount}); } shouldComponentUpdate 当组件接收到新的属性和状态改变的话,都会触发调用shouldComponentUpdate(...),函数原型如下: booleanshouldComponentUpdate(objectnextProps,objectnextState ) 输入参...
shouldComponentUpdateis called after props or state are changed (and aftercomponentWillReceiveProps), but before it renders. It’s unique among lifecycle functions in that it is expected to return a boolean value. If false,renderwill not be called. This can be very useful for skipping unnecessa...
classAppextendsComponent{componentWillReceiveProps(nextProps){接受更新props阶段,可以使用setState}shouldComponentUpdate(nextProps,nextState){是否更新props和state阶段,默认为true,代表渲染(更新) 可以在这个阶段对nextProps和当前this.props进行对比,以便确认是否渲染(更新)}componentWillUpdate(nextProps,nextState){与...
varMyComponent = React.createClass({ statics: { customMethod:function(foo) { returnfoo ==='bar'; } }, render:function() { } }); MyComponent.customMethod('bar');// true displayName 1 string displayName 用于debug时候的定位。 生命周期方法 实例化 当首次使用组件类时,下面这些方法依次被调用。
这个方法可以让你处理一些必要的清理操作,比如无效的timers、interval,或者取消网络请求,或者清理任何在componentDidMount()中创建的DOM元素(elements); 相关setState(Object/Function) 解释 通过事件(event handlers)或服务请求回调(server request callbacks), 触发UI更新(re-render); ...
React Function Component: Lifecycle(React 函数组件之生命周期) React Functional Component: Mount(React 函数组件之挂载) React Functional Component: Update(React 函数组件之:更新) Pure React Function Component(纯 React 函数组件) React Function Component: Export and Import(React 函数组件之:Export 和 Import...
componentWillMount里允许我们初始化前最后一次对state进行修改,而不会触发重新渲染。 var A = React.createClass({ getInitialState: function () { return {init: false}; }, componentWillMount: function () { this.setState({init: true}); console.log('A componentWillMount'); ...
State and Lifecycle - React 状态和生命周期 之前一个时钟的例子one of the previous sections. 到目前为止,我们只知道一种方法来更新UI。 我们称为 ReactDOM.render() 来渲染输出to change the rendered output: functiontick(){constelement=(Hello,world!Itis{newDate().toLocaleTimeString()}.);React...
Remember, the setState function takes argument(s) of state, props(optional) if needed. JavaScript Copy Code onClick={() => this.setState((state) => { return { count: state.count + 1 }; }) } See state with class component in Codepen Lifecycle Methods Finally, let’s talk about...
componentDidMount:function() { console.log("Did mount"); }, componentWillUnmount:function() { console.log("Byebye"); }, render:function(){ console.log("render");return{this.state.val}} }); window.Render=function() { React.render(<...