# React state // React Component First Letter Capital class based or function based // maximum 80 character in one line // make more readable // space with 2 indent // one function one work, to create accuracy // Event => event function // alway give Naming: (function name)Handler, (function name)Handle, (function name)Event // setState is a Setter function ```javascript= class Sum extends React.Component { constructor(props) { super(props); this.state = { firstValue: '', work: '' } this.myDivHandler = this.myDivHandler.bind(this); } myDivHandler(event) { // code this.setState({ firstValue: event.target.value }) } render() { return ( <div className="my-div" id="myDiv"> <input onChange={this.myDivHandler} value={this.state.firstValue} /> Simple Div {this.state.firstValue} {/* {getter method} */} {console.log('asss')} {this.props.fruit} </div> ); } } ReactDOM.render(<Sum fruit="Apple" />, document.getElementById("#mount")); ```