react用PropTypes检测类型

用PropTypes检测类型

注意：React v15.5.已经把React.PropTypes分离了，请用prop-types库替代

npm install --save prop-types

项目做大了后经常就会出现类型错误的bug，平时可以用JS插件如Flow,TypeScript检测。如果不用这些插件的话，React也提供了检测工具,给某个组件检测props类型时，可以给他扩展一个propTypes属性：

import PropTypes from 'prop-types';class Greeting extends React.Component {  render() {    return (      <h1>Hello, {this.props.name}</h1>    );  }}// name只能是字符串Greeting.propTypes = {  name: PropTypes.string};

如果类型不是字符串的时候就会报错，这种检测只在生产环境中使用

PropTypes

以下是默认类型

import PropTypes from 'prop-types';MyComponent.propTypes = {  // You can declare that a prop is a specific JS primitive. By default, these  // are all optional.  optionalArray: PropTypes.array,  optionalBool: PropTypes.bool,  optionalFunc: PropTypes.func,  optionalNumber: PropTypes.number,  optionalObject: PropTypes.object,  optionalString: PropTypes.string,  optionalSymbol: PropTypes.symbol,  // Anything that can be rendered: numbers, strings, elements or an array  // (or fragment) containing these types.  optionalNode: PropTypes.node,  // A React element.  optionalElement: PropTypes.element,  // You can also declare that a prop is an instance of a class. This uses  // JS's instanceof operator.  optionalMessage: PropTypes.instanceOf(Message),  // You can ensure that your prop is limited to specific values by treating  // it as an enum.  optionalEnum: PropTypes.oneOf(['News', 'Photos']),  // An object that could be one of many types  optionalUnion: PropTypes.oneOfType([    PropTypes.string,    PropTypes.number,    PropTypes.instanceOf(Message)  ]),  // An array of a certain type  optionalArrayOf: PropTypes.arrayOf(PropTypes.number),  // An object with property values of a certain type  optionalObjectOf: PropTypes.objectOf(PropTypes.number),  // An object taking on a particular shape  optionalObjectWithShape: PropTypes.shape({    color: PropTypes.string,    fontSize: PropTypes.number  }),  // 每个类型后面跟 `isRequired` 表示props一定要有这个类型，否则报错  requiredFunc: PropTypes.func.isRequired,  // A value of any data type  requiredAny: PropTypes.any.isRequired,  // You can also specify a custom validator. It should return an Error  // object if the validation fails. Don't `console.warn` or throw, as this  // won't work inside `oneOfType`.  customProp: function(props, propName, componentName) {    if (!/matchme/.test(props[propName])) {      return new Error(        'Invalid prop `' + propName + '` supplied to' +        ' `' + componentName + '`. Validation failed.'      );    }  },  // You can also supply a custom validator to `arrayOf` and `objectOf`.  // It should return an Error object if the validation fails. The validator  // will be called for each key in the array or object. The first two  // arguments of the validator are the array or object itself, and the  // current item's key.  customArrayProp: PropTypes.arrayOf(function(propValue, key, componentName, location, propFullName) {    if (!/matchme/.test(propValue[key])) {      return new Error(        'Invalid prop `' + propFullName + '` supplied to' +        ' `' + componentName + '`. Validation failed.'      );    }  })};

限制一个child

传入的props。children只能包含一个兄弟元素(独生子)，否则报错。可以有子元素。

import PropTypes from 'prop-types';class MyComponent extends React.Component {  render() {    // 必须是一个元素否则报错    const children = this.props.children;    return (      <div>        {children}      </div>    );  }}MyComponent.propTypes = {  children: PropTypes.element.isRequired};

prop默认值

用defaultProps给prop设置默认值

class Greeting extends React.Component {  render() {    return (      <h1>Hello, {this.props.name}</h1>    );  }}// s设置默认值Greeting.defaultProps = {  name: 'Stranger'};// 渲染结果 "Hello, Stranger":ReactDOM.render(  <Greeting />,  document.getElementById('example'));

默认值是为了确保父调用组件时没有传递props值而设置的一个默认展示结果。类型检测是在解析完默认值执行，所以类型检测依然对defaultProps有效