


What are the uses of React component refs? Detailed explanation of the role of react component refs and its use
This article mainly explains the detailed explanation of react component refs. Now let’s take a look at the content of the text
ref As the name suggests, we know that in fact it can be The stand is a reference for a component, which can also be said to be a logo. As a component attribute, its attribute value can be a string or a function.
Actually, the use of ref is not necessary. Even in the scenarios where it is applicable, it is not necessary, because the functions implemented using ref can also be converted into other methods. However, since ref has its applicable scenarios, it means that ref has its own advantages. Regarding this and the applicable scenarios of ref, the official documentation says this:
After returning the UI structure from the render method, you may want to break out of the limitations of the React virtual DOM and use the component instance returned by render Call certain methods on. Generally speaking, this is not necessary for data flow in the application, because the reactive data flow always ensures that the latest props are passed to each child output from render(). However, there are still several scenarios where using this approach is necessary or beneficial: finding the DOM markup of the rendered component (which can be thought of as the DOM identification ID), using React components in a large non-React application Or convert your existing code into React.
Let’s take a look at such a scenario (the following example is often used to explain ref, so it can be seen that the scenario described below should be more classic): using an event to make the element 's value is set to the empty string, and the element is given focus.
var App = React.createClass({
getInitialState: function() {
return {userInput: ''};
},
handleChange: function(e) {
this.setState({userInput: e.target.value});
},
clearAndFocusInput: function() {
this.setState({userInput: ''}); // Set value Is the empty string
value={this.state.userInput}
onChange={this.handleChange}
/>
onClick ={this.clearAndFocusInput}
Clicking the button notifies the input element to set the value to the empty string, but it has not yet been implemented to allow the input element to gain focus. This is a bit difficult to implement because what is returned in render() is not the actual combination of subcomponents, just a description of a specific instance at a specific time. This sentence feels quite confusing. In fact, what render returns is
virtual DOM
, not the real DOM. So we don't need to focus only on those components returned from render().
Speaking of which, it doesn’t help us much in how to achieve focus. To achieve the function of getting focus, we need to use ref. We mentioned above that there are two types of ref values, one is a string and the other is a callback function.
ref string attribute
React supports a special attribute that you can add to any component returned by render(). This means that the component returned by render() is marked so that the component instance can be easily located. This is what ref is for.
The form of ref is as follows
To access this instance, you can access it through this.refs:
this.refs.myInput
In previous versions, we could access the DOM of the component through React.findDOMNode(this.refs.myInput). But now, the findDOMNode function has been abandoned and can be accessed directly using this.refs.myInput. (If you want to learn more, go to the PHP Chinese website React Reference Manual column to learn)
ref callback function
The ref attribute can also be a callback function instead of a name. This function will be executed immediately after the component is mounted. The referenced component will be used as a parameter to the function, which can use the component parameter immediately or save it for later use.
The form is also relatively simple:
render: function() {
return
},
componentDidMount: function() {
this._input.focus();
},
or
render: function() {
return (
if (input != null) {
input.focus();
}
}} />
);
},
It should be noted here that when this reference component is uninstalled and this ref changes, the parameter value of the previous ref will be null. This will effectively prevent memory leaks. Therefore, there will be an if judgment in the above code:
if(input != null){
input.focus();
}
The above describes the usage scenarios of ref and methods, below we will complete the above example to achieve the function of getting focus
var App = React.createClass({
getInitialState: function() {
return {userInput: ''};
},
handleChange: function(e) {
this.setState({userInput: e.target.value});
},
clearAndFocusInput: function() {
this.setState({userInput: ''}); // Clear the input
// We wish to focus the now!
if (this.refs.myTextInput !== null) {
this.refs.myTextInput.focus();
}
},
render: function() {
return (
value={this.state.userInput}
onChange={this.handleChange}
ref=”myTextInput”
/>
type="button"
value="Reset And Focus"
onClick={this.clearAndFocusInput}
/>
);
}
});
ReactDOM.render(
document.getElementById('content')
);
在这个例子中, render 函数返回一个 实例的描述。但是真正的实例通过 this.refs. myTextInput获取。只要 render 返回的某个子组件带有 ref="myTextInput" ,this.refs. myTextInput就会获取到正确的实例。
上面就是ref的所有内容,更多关于ref的介绍可以参考Ref to Components。
本篇文章到这就结束了(想看更多就到PHP中文网React使用手册栏目中学习),有问题的可以在下方留言提问。
The above is the detailed content of What are the uses of React component refs? Detailed explanation of the role of react component refs and its use. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Netflixusesacustomframeworkcalled"Gibbon"builtonReact,notReactorVuedirectly.1)TeamExperience:Choosebasedonfamiliarity.2)ProjectComplexity:Vueforsimplerprojects,Reactforcomplexones.3)CustomizationNeeds:Reactoffersmoreflexibility.4)Ecosystema

The React ecosystem includes state management libraries (such as Redux), routing libraries (such as ReactRouter), UI component libraries (such as Material-UI), testing tools (such as Jest), and building tools (such as Webpack). These tools work together to help developers develop and maintain applications efficiently, improve code quality and development efficiency.

Netflix uses React as its front-end framework. 1) React's componentized development model and strong ecosystem are the main reasons why Netflix chose it. 2) Through componentization, Netflix splits complex interfaces into manageable chunks such as video players, recommendation lists and user comments. 3) React's virtual DOM and component life cycle optimizes rendering efficiency and user interaction management.

React is a JavaScript library developed by Meta for building user interfaces, with its core being component development and virtual DOM technology. 1. Component and state management: React manages state through components (functions or classes) and Hooks (such as useState), improving code reusability and maintenance. 2. Virtual DOM and performance optimization: Through virtual DOM, React efficiently updates the real DOM to improve performance. 3. Life cycle and Hooks: Hooks (such as useEffect) allow function components to manage life cycles and perform side-effect operations. 4. Usage example: From basic HelloWorld components to advanced global state management (useContext and

React's future will focus on the ultimate in component development, performance optimization and deep integration with other technology stacks. 1) React will further simplify the creation and management of components and promote the ultimate in component development. 2) Performance optimization will become the focus, especially in large applications. 3) React will be deeply integrated with technologies such as GraphQL and TypeScript to improve the development experience.

The advantages of React are its flexibility and efficiency, which are reflected in: 1) Component-based design improves code reusability; 2) Virtual DOM technology optimizes performance, especially when handling large amounts of data updates; 3) The rich ecosystem provides a large number of third-party libraries and tools. By understanding how React works and uses examples, you can master its core concepts and best practices to build an efficient, maintainable user interface.

Netflix mainly uses React as the front-end framework, supplemented by Vue for specific functions. 1) React's componentization and virtual DOM improve the performance and development efficiency of Netflix applications. 2) Vue is used in Netflix's internal tools and small projects, and its flexibility and ease of use are key.

React is a front-end framework for building user interfaces; a back-end framework is used to build server-side applications. React provides componentized and efficient UI updates, and the backend framework provides a complete backend service solution. When choosing a technology stack, project requirements, team skills, and scalability should be considered.
