本篇文章给大家带来的内容是关于react中类型检查的介绍，有一定的参考价值，有需要的朋友可以参考一下，希望对你有所帮助。
Typechecking With PropTypes
类型检查是为了确保传入组件的参数正确性。
通常在项目中可以使用Flow或者TypeScript来实现。
React提供了PropTypes来检查类型。
示例：
import PropTypes from 'prop-types';class Greeting extends React.Component { render() { return ( Hello, {this.props.name}
); }}Greeting.propTypes = { name: PropTypes.string};
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PropTypes
import PropTypes from 'prop-types';MyComponent.propTypes = { // You can declare that a prop is a specific JS type. 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 }), // You can chain any of the above with `isRequired` to make sure a warning // is shown if the prop isn't provided. 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.' ); } })};
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Requiring Single Child
import PropTypes from 'prop-types';class MyComponent extends React.Component { render() { // This must be exactly one element or it will warn. const children = this.props.children; return ( {children}
); }}MyComponent.propTypes = { children: PropTypes.element.isRequired};
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Default Prop Values
class Greeting extends React.Component { render() { return ( Hello, {this.props.name}
); }}// Specifies the default values for props:Greeting.defaultProps = { name: 'Stranger'};// Renders "Hello, Stranger":ReactDOM.render( , document.getElementById('example'));
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以上内容在实现一个通用React组件时非常有用。类型检查和参数默认值一起使用，保证组件的正常运行。
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