45 lines
1.0 KiB
Markdown
45 lines
1.0 KiB
Markdown
### Timer
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Renders a timer component.
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The timer state is initially set to zero. When the `Tick!` button is clicked, `timer` is incremented periodically at the given `interval`. The `setInterval` is cleared once the desired `time` is reached. `time` and `interval` are the required props.
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```jsx
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class App extends Component {
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constructor(props) {
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super(props);
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this.state = {timer: 0}
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this.interval = null
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}
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tick = () => {
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this.reset()
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this.interval = setInterval(() => {
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if (this.state.timer < this.props.time) {
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this.setState({timer: this.state.timer + 1})
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}else{
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clearInterval(this.interval)
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}
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}, this.props.interval)
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}
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reset = () => {
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this.setState({timer: 0})
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clearInterval(this.interval)
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}
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render() {
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return (
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<div>
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<span style={{fontSize: 100}}>{this.state.timer}</span>
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<button onClick={this.tick}>Tick!</button>
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<button onClick={this.reset}>Reset</button>
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</div>
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);
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}
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}
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```
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```jsx
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ReactDOM.render(<Timer time={5} interval={1000} />, document.getElementById('root'));
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``` |