Viewing github.com/facebook/react/fixtures/concurrent/time-slicing/src/index.js

import React, {PureComponent, startTransition} from 'react';

import {createRoot} from 'react-dom/client';

```
import _ from 'lodash';
```
```
import Charts from './Charts';
```
```
import Clock from './Clock';
```
```
import './index.css';
```
```
let cachedData = new Map();
```
```
class App extends PureComponent {
```
```
  state = {
```
```
    value: '',
```
```
    strategy: 'sync',
```
```
    showDemo: true,
```
```
    showClock: false,
```
```
  };
```
```
  // Random data for the chart
```
```
  getStreamData(input) {
```
```
    if (cachedData.has(input)) {
```
```
      return cachedData.get(input);
```
```
    }
```

    const multiplier = input.length !== 0 ? input.length : 1;

```
    const complexity =
```

      (parseInt(window.location.search.slice(1), 10) / 100) * 25 || 25;

```
    const data = _.range(5).map(t =>
```

      _.range(complexity * multiplier).map((j, i) => {

```
        return {
```
```
          x: j,
```

          y: (t + 1) * _.random(0, 255),

```
        };
```
```
      })
```
```
    );
```
```
    cachedData.set(input, data);
```
```
    return data;
```
```
  }
```
```
  componentDidMount() {
```

    window.addEventListener('keydown', e => {

      if (e.key.toLowerCase() === '?') {

```
        e.preventDefault();
```
```
        this.setState(state => ({
```
```
          showClock: !state.showClock,
```
```
        }));
```
```
      }
```
```
    });
```
```
  }
```
```
  handleChartClick = e => {
```
```
    if (this.state.showDemo) {
```
```
      if (e.shiftKey) {
```

        this.setState({showDemo: false});

```
      }
```
```
      return;
```
```
    }
```

    if (this.state.strategy !== 'async') {

```
      this.setState(state => ({
```
```
        showDemo: !state.showDemo,
```
```
      }));
```
```
      return;
```
```
    }
```
```
    if (this._ignoreClick) {
```
```
      return;
```
```
    }
```
```
    this._ignoreClick = true;
```
```
    startTransition(() => {
```

      this.setState({showDemo: true}, () => {

```
        this._ignoreClick = false;
```
```
      });
```
```
    });
```
```
  };
```

  debouncedHandleChange = _.debounce(value => {

    if (this.state.strategy === 'debounced') {

```
      this.setState({value: value});
```
```
    }
```
```
  }, 1000);
```
```
  renderOption(strategy, label) {
```

    const {strategy: currentStrategy} = this.state;

```
    return (
```

      <label className={strategy === currentStrategy ? 'selected' : null}>

```
        <input
```
```
          type="radio"
```

          checked={strategy === currentStrategy}

          onChange={() => this.setState({strategy})}

```
        />
```
```
        {label}
```
```
      </label>
```
```
    );
```
```
  }
```
```
  handleChange = e => {
```
```
    const value = e.target.value;
```
```
    const {strategy} = this.state;
```
```
    switch (strategy) {
```
```
      case 'sync':
```
```
        this.setState({value});
```
```
        break;
```
```
      case 'debounced':
```

        this.debouncedHandleChange(value);

```
        break;
```
```
      case 'async':
```

        // TODO: useTransition hook instead.

```
        startTransition(() => {
```
```
          this.setState({value});
```
```
        });
```
```
        break;
```
```
      default:
```
```
        break;
```
```
    }
```
```
  };
```
```
  render() {
```
```
    const {showClock} = this.state;
```

    const data = this.getStreamData(this.state.value);

```
    return (
```
```
      <div className="container">
```
```
        <div className="rendering">
```

          {this.renderOption('sync', 'Synchronous')}

          {this.renderOption('debounced', 'Debounced')}

          {this.renderOption('async', 'Concurrent')}

```
        </div>
```
```
        <input
```

          className={'input ' + this.state.strategy}

          placeholder="longer input → more components and DOM nodes"

          defaultValue={this.state.input}

```
          onChange={this.handleChange}
```
```
        />
```

        <div className="demo" onClick={this.handleChartClick}>

```
          {this.state.showDemo && (
```

            <Charts data={data} onClick={this.handleChartClick} />

```
          )}
```

          <div style={{display: showClock ? 'block' : 'none'}}>

```
            <Clock />
```
```
          </div>
```
```
        </div>
```
```
      </div>
```
```
    );
```
```
  }
```
```
}
```

const container = document.getElementById('root');

```
const root = createRoot(container);
```
```
root.render(<App />);
```

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