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In React, the form is divided into two parts: controlled components and uncontrolled components. 4.7.1 controlled components We know that form elements in HTML can input data (or delete), that is, they have their own variable state. For example, in a text box, you can enter or delete content in the text box, and the entered content can be cal ...

1, What problems have been solved? Hook is a special function starting with use (useState, useEffect, etc.), which can only be used inside the function component. It allows you to use state and other React features without writing class. For example, useState is equivalent to the state object in the class component. 1. Update instructions for ...

Previously on: Actual online chat room course of React full Hook project (I): basic functions Actual online chat room course of React full Hook project (II): quotation and topic function text What should chat have? Background music, tea and wine, snacks, I can't realize the last two, but we can add a background music function to our online c ...

Since the implementation of React Hooks, Redux is out of place as a state management scheme. Dan Abramov mentioned "You might not need Redux" a long time ago. Developers must write a lot of "pattern code". Cumbersome and repetition are not tolerated by developers. In addition to the fact that the concepts such as actions/red ...

setState has three features: Code first: export default class App extends Component { state = { n: 1 } hClick = () => { this.setState({n: 100}) console.log(this.state.n)// How much is printed here? console.log(document.getElementById('span').innerHTML) // How much is printed here? } render () { return ( ...

props verification - basic usage: In the previous blog, we mentioned the verification of props, as shown in the figure:   Props verification: for child components, props is foreign (it accepts the parameters passed by the parent component), and it is impossible to guarantee the format of data passed in by the component user. With type ...

Knowledge points: webpack with react environmentRealize adaptationConfigure dynamic routing webpack with react environment Installation dependency npm init -ycnpm install react react-dom @types/react @types/react-dom react-router-dom @types/react-router-dom antd redux react-redux @types/react-redux react-thunk redux-logger @types/redux-logg ...

For a high-performance react component, it is important to reduce redrawing and rearrangement, server rendering, and so on. In a react application, the logic is organized as a react component, which splits the UI into separate, reusable components. Then the component performance optimization is maliciously considered from the perspective of co ...

Preface Lifecycle of components and associated hook functions text Lifecycle of components: The life cycle is the entire process from creation of a component to not running unloaded from a page. There are many functions that run throughout the life cycle, which are hook functions. Only class components have a life cycle. Hook function at cre ...

preface 1. Relevant principles of react 2.React performance optimization text Introduction to related principles of React setState method, which updates the data asynchronously, and calls the setState method several times, and finally only re renders the render method once class App extends React.Component{ state={ num:0 } ...