React.js props-JS Tutorial-php.cn

React.js props

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Release： 2018-03-13 14:51:27

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This time I will bring you the props of React.js. What are the things to note when using the props of React.js?The following is a practical case, let’s take a look.

The parent component passes the value to the child component

<Son userid={123}/>

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Receive the value passed by the parent component in the Son component

<p>接收到的父页面的属性 -- userid: {this.props.userid} username:{this.props.username}</p>

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Of course, you can also set the parameters to be passed on the Son page Types and default values

// 给属性设置类型BodyIndex.propTypes = {    // isRequired 必须的参数
    userid: React.PropTypes.number.isRequired,
    username: React.PropTypes.string
}// 设置默认值BodyIndex.defaultProps = {
    username: &#39;哈哈&#39;}

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For details on setting the type, please refer to the official documentation

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&#39;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([&#39;News&#39;, &#39;Photos&#39;]),  // 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&#39;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&#39;t `console.warn` or throw, as this
  // won&#39;t work inside `oneOfType`.
  customProp: function(props, propName, componentName) {    if (!/matchme/.test(props[propName])) {      return new Error(        &#39;Invalid prop `&#39; + propName + &#39;` supplied to&#39; +        &#39; `&#39; + componentName + &#39;`. Validation failed.&#39;
      );
    }
  },  // 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&#39;s key.
  customArrayProp: PropTypes.arrayOf(function(propValue, key,       componentName, location, propFullName) {    if (!/matchme/.test(propValue[key])) {      return new Error(        &#39;Invalid prop `&#39; + propFullName + &#39;` supplied to&#39; +        &#39; `&#39; + componentName + &#39;`. Validation failed.&#39;
      );
    }
  })
 };

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The Son component passes the properties passed from the parent component to the grandchild component

Through the expansion
operation Symbol {...this.props}, pass all the properties passed from the parent component to its own child component (grandchild component) id={1234} is passed by the Son component itself to the grandchild component Attributes

<GrandSon {...this.props} id={1234}/>

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Call the attributes passed from the Son component in the grandson component

<p>{this.props.userid} {this.props.username} {this.props.id}</p>

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refs: It is the only reliable way to access the DOM node inside the component

to the label Add ref

<input ref=&#39;submitButton&#39; type="button" value=&#39;提交&#39; onClick={() => this.changeUserInfo(99)}/>

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When you want to get the dom, get it through this.refs.xxx

this.refs.submitButton.style.color = &#39;red&#39;;

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Note:

Do not call Refs before render or render;

Don’t abuse Refs, if you can’t use it, don’t use it!!!

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!