React三大属性之props的使用详解

//父组件传值
class Father extends React.PureComponent{
    render(){
        return (
            <Son value={"son"} />
        )
    }
}

class Son extends React.PureComponent{
    render(){
        return (
            <div>this data is {this.props.value}</div>
        )
    }
}

function Fa(){
    return (
        <Son value={"son"} />
    )
}

function Son(props){
    return (
        <div>this data is {props.value}</div>
    )
}

//父组件给子组件传值以及说过了，现在总结子组件给父组件传值,此时往往需要父组件给子组件先传一个props函数，子组件通过调用传入的函数传值改变父组件的值
export default class Fa extends Component {
    state = {faValue:'Fa1'}

    changeFa = (value)=>{
        this.setState(()=>{
            return {faValue:value}
        })
    }
    render() {
        return (
            <>
                <h1>Fa's value is {this.state.faValue}</h1>
                <Son changeFa={this.changeFa}/>
            </>
        )
    }
}

export default class Son extends React.PureComponent{

    changeValue = ()=>{
        this.props.changeFa(this.inputRef.value)
    }
    render() {
        return (
            <>
                <input type="text" placeholder={"请输入您的值"} ref={(el)=>{this.inputRef = el}}/>
                <button onClick={this.changeValue}>change</button>
            </>
        )
    }
}

function Fa(){
    const [faValue,setFaValue] = useState("Fa1")

    const changeFa = (value)=>{
        setFaValue(value)
    }
    return (
        <div>
            <h1>Fa's value is {faValue}</h1>
            <Son changeFa={changeFa} />
        </div>
    )
}

function Son(props){
    const inputValue = useRef("")
        //定义改变fa组件的值的函数
        const changeFaValue = ()=>{
            props.changeFa(inputValue.current.value)
        }
        return (
            <>
                <input type="text" placeholder={"请输入您要改变的值"} ref={inputValue}/>
                <button onClick={changeFaValue}>change value</button>
            </>
        )
}

//比如针对之前的输入案例，我需要给兄弟组件传一个值value，如果不用props,我们该怎么写
Bro:
export default class Bro extends Component {

    componentDidMount() {
        this.sonData =  PubSub.subscribe("brother",(msg,data)=>{
            console.log("Bro Component have recived the msg",data);
        })
    }

    componentWillUnmount() {
        PubSub.unsubscribe(this.sonData)
    }

    render() {
        return (
            <>
                <div>brother</div>
            </>
        )
    }
}
Son:
export default class Son extends React.PureComponent{

    changeValue = ()=>{
        PubSub.publish("brother",this.inputRef.value)
    }

    render() {
        return (
            <>
                <input type="text" placeholder={"请输入您的值"} ref={(el)=>{this.inputRef = el}}/>
                <button onClick={this.changeValue}>change</button>
            </>
        )
    }
}