componentdidmount useeffect equivalent code example

Example 1: useeffect componentdidmount

import React, { useState, useEffect } from 'react';
function Example() {
  const [count, setCount] = useState(0);

  // Similar to componentDidMount and componentDidUpdate:  
  useEffect(() => {    
    // Update the document title using the browser API    
    document.title = `You clicked ${count} times`;  
  });

  );
}

Example 2: alternative for componentdidmount

import React, { useEffect } from 'react'const SampleComponent = () => {  useEffect(() => {    // code to run on component mount  }, [])return (<div>foo</div>)}export SampleComponent

Example 3: useeffect componentdidmount

useEffect(() => {
    messagesRef.on('child added', snapshot => {
    const message = snapshot.val();
    message.key = snapshot.key;

    setMessages(messages.concat(message)); // See Note 1
}, []); // See Note 2

Tags:

Misc Example

Related