life cycle methods in react hooks code example

Example 1: useEffect

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`;
  });

  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

Example 2: useeffect react

useEffect(() => {
  window.addEventListener('mousemove', () => {});

  // returned function will be called on component unmount 
  return () => {
    window.removeEventListener('mousemove', () => {})
  }
}, [])

Example 3: react lifecycle hooks

class Content extends React.Component {
  // ...
  componentWillMount() {
    this.setState({ activities: data });
  }
  // ...
}

Example 4: react lifecycle hooks

class ActivityItem extends React.Component {
  render() {
    const { activity } = this.props;

    return (
      <div className='item'>
        <div className={'avatar'}>
          <img
            alt='avatar'
            src={activity.actor.avatar_url} />
        </div>

        <span className={'time'}>
          {moment(activity.created_at).fromNow()}
        </span>
        
        <p>{activity.actor.display_login} {activity.payload.action}</p>
        <div className={'right'}>
          {activity.repo.name}
        </div>
      </div>
    )
  }
}