React

by seo gyeongseok

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 MyInput extends React.Component {
  constructor(props) {
    super(props)
    this.state = { value: props.value || '' }
  }
  
  render() {
  	  const handler = (e) => {
      	// this.setState({ value: e.target.value });
        this.props.changeFn(e.target.value);
      }
      return (<input key='test' value={this.state.value} onChange={handler}></input>);
  }
}

class TodoApp extends React.Component {
  constructor(props) {
    super(props)
    this.state = {
      value: 'test...!!',
    };
    this.changeFn = this.changeFn.bind(this);
  }
  
  changeFn(d) {
    console.log('hwi...', d);
    this.setState({ value: d || '' }); 
  }
  
  shouldComponentUpdate(nextProps, nextState) {
    console.log('hwi.???', this.state.value);
    return true;
  }
  
  render() {
    console.log('hwi...', this.state.value);

    return (
      <div>
        <MyInput value={this.state.value || ''} changeFn={this.changeFn} />
        <h2>Todos:</h2>
      </div>
    )
  }
}

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