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Lifecycle

LC 1.

shouldComponentUpdate = (nextProps, nextState) => {
    console.log("nextProps===>>>", nextProps)
    console.log("nextState===>>>", nextState)
    return true
}

componentWillUpdate = (nextProps, nextState) => {
    console.log("nextProps===>>>", nextProps)
    if(this.state === nextState) {
        this.setState({
        })
    }
}

LC 2.

shouldComponentUpdate = (nextProps, nextState) => {
    console.log("nextProps===>>>", nextProps)
    console.log("nextState===>>>", nextState)
    return true
}

getSnapshotBeforeUpdate = () => {
    console.log("Test")
    // return null
    // return {message: "SanapShot!"}
}

componentDidUpdate = (prevProps, prevState, snapshot) => {
    console.log("Test")
    console.log("snapshot===>>", snapshot)
}

LS3:-

componentWillUnmount() {
    console.log("unmount===>>")
}

Note:- Run right before the component is removed (cleanUp Work).

Hooks1

useEffect(() => {
    console.log("useEffect===>>")
    setTimeout(() => {
        alert("saved data to cloud")
    }, 1000)
}, [])

Note:- [ ] point all the variable or data.

we can write [ ] as requirement else not

we can write multiple useEffect