React

by Abdul Ahmad

HTML

<div id="app"></div>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#app {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  transition: all 0.2s;
}

li {
  margin: 8px 0;
}

h2 {
  font-weight: bold;
  margin-bottom: 15px;
}

.done {
  color: rgba(0, 0, 0, 0.3);
  text-decoration: line-through;
}

input {
  margin-right: 5px;
}

React

class Child extends React.PureComponent {
	render() {
  	console.log('child render');
  	return (
    	<div>child</div>
    );
  }
}

class TodoApp extends React.Component {
	state = { bool: false };
  
  reRender = () => {
  	const { bool } = this.state;
    this.setState({ bool: !bool });
  }

  render() {
  	console.log('parent render');
  
    return (
      <div>
        <button onClick={this.reRender}>re render</button>
        <div>
          parent
        </div>
        <Child />
      </div>
    )
  }
}

ReactDOM.render(<TodoApp />, document.querySelector("#app"))