What are the methods of react communication?

React communication methods include: 1. Use props for parent-child component communication; 2. Use callback functions for child-parent component communication; 3. Use variable promotion for sibling component communication; 4. Use Context for cross-component communication; 5. Use node’s events module for single instance communication; 6. Use redux to share data communication.

The operating environment of this tutorial: Windows7 system, react17.0.1 version, Dell G3 computer.

Six communication methods of React

1. Props parent-child communication
2. Callback function, child-father communication
3 .Variable promotion, sibling component communication
4.Context, cross-component communication
5.Single instance communication of node’s events module
6.redux shared data communication

1.propsFather-child communication

function Children(props) {
      return (
        <div>
          <p>Children</p>
          <p>{props.text}</p>
        </div>
      )
    }
    function Parent() {
      return (
        <div>
          <p>Parent</p>
          <Children text="这是爸爸传给你的东西"></Children>
        </div>
      )
    }
    
    export default Parent

2.Callback function, child-parent communication

function Children(props) {
  return (
    <div>
      <p>Children</p>
      <p>{props.text}</p>
      <button onClick={() => { props.handleChange(&#39;改变了&#39;) }}>
        点击我改变爸爸传给我的东西
      </button>
    </div>
  )
}

function Parent() {
  let [text, setText] = useState(&#39;这是爸爸传给你的东西&#39;)
  function handleChange(val) {
    setText(val)
  }
  return (
    <div>
      <p>Parent</p>
      <Children handleChange={handleChange} text={text}></Children>
    </div>
  )
}
export default Parent

3. Variable promotion, communication among brothers

function Children(props) {
  return (
    <div>
      <p>Children</p>
      <button onClick={() => { props.setText(&#39;我是Children发的信息&#39;) }}>给Children1发信息</button>
    </div>
  )
}
function Children1(props) {
  return (
    <div>
      <p>Children1</p>
      <p>{props.text}</p>
    </div>
  )
}

function App() {
  let [text, setText] = useState(&#39;&#39;)
  return (
    <>
      <div>APP</div>
      <Children setText={setText}></Children>
      <Children1 text={text}></Children1>
    </>
  )
}
export default App

4.Context, communication across groups

Old way of writing

class Children extends React.Component {
  static contextTypes = {
    text: PropsType.string
  }
  render() {
    return (
      <div>
        <p>Children</p>
        <p>{this.context.text}</p>
      </div>
    )
  }
}

class Parent extends React.Component {
  static childContextTypes = {
    text: PropsType.string
  }
  getChildContext() {
    return {
      text: &#39;我是爸爸的信息&#39;
    }
  }
  render() {
    return (
        <div>
          <p>Parent</p>
          <Children></Children>
        </div>
    )
  }
}
export default Parent

New way of writing

const { Consumer, Provider } = React.createContext()

class Children extends React.Component {
  render() {
    return (
      <Consumer>
        {
          (value) => (
            <div>
              <p>Children1</p>
              <p>{value.text}</p>
            </div>
          )
        }
      </Consumer>
    )
  }
}

class Parent extends React.Component {
  render() {
    return (
      <Provider value={{ text: &#39;我是context&#39; }}>
        <div>
          <p>Parent</p>
          <Children1></Children1>
        </div>
      </Provider>
    )
  }
}

export default Parent

5.Single instance communication of the events module of node

function Children(props) {
  return (
    <div>
      <p>Children</p>
      <p>{props.text}</p>
      <button onClick={() => { props.event.emit(&#39;foo&#39;) }}>点击我改变爸爸传给我的东西</button>
    </div>
  )
}

function Parent() {
  let [text, setText] = useState(&#39;这是爸爸传给你的东西&#39;)
  let event = new Events()
  event.on(&#39;foo&#39;, () => { setText(&#39;改变了&#39;) })
  return (
    <div>
      <p>Parent</p>
      <Children event={event} text={text}></Children>
    </div>
  )
}
export default Parent

Note⚠️: For this kind of communication, remember to introduce the events module at the top, no need to install, node its own module.

6.redux shared data communication

store.js

import { createStore } from 'redux'

let defaultState = {
    text: '我是store'
}

let reducer = (state = defaultState, action) => {
    switch (action) {
        default: return state
    }
}

export default createStore(reducer)

child.js

import React from 'react'

import { connect } from 'react-redux'

class Child extends React.Component {
    render() {
        return (
            <div>Child<p>{this.props.text}</p></div>
        )
    }
}

let mapStataToProps = (state) => {
    return {
        text: state.text
    }
}

export default connect(mapStataToProps, null)(Child)

Parent.js

class Parent extends React.Component {
  render() {
    return (
      <Provider store={store}>
        <div>
          <p>Parent</p>
          <Child></Child>
        </div>
      </Provider>
    )
  }
}

export default Parent

Note: Remember to install redux and react-redux.

[Related recommendations: Redis video tutorial]

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