Learn React Hooks

Using an Effect Hook

In the world of Hooks, the componentDidMount and componentDidUpdate life cycle methods are combined in the useEffect Hook, which—when not specifying a dependency array—triggers whenever any props in the component change.

So, instead of using a class component, we can now define a function component with an Effect Hook, which does the same thing as before. The function passed to the Effect Hook is called "effect function":

import React, { useEffect } from 'react'function App ({ title }) {    useEffect(() => {        document.title = title    })    return (        <div>Test App</div>    )}

And that's all we need to do! The Hook that we have defined will call our effect function every time any props change.