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JavaScript

Posted by Kristian Woods
Kristian Woods
23,414 Points

Why couldn't the Timer example have been simpler?

I have created the same timer, with the exact same functionality - yet, doesn't include all the excess e.g. elapsed time etc. However, I might be missing something in mine, that Guil has in his?

However, here is my version 

class App extends Component {
  state = {
    isRunning: false,
    time: 0
  };

  tick = () => {
    this.setState(prevState => {
      return {
        time: (prevState.time += 1)
      };
    });
  };

  handleTimer = () => {
    this.setState(prevState => {
      return {
        isRunning: !prevState.isRunning
      };
    });
    if (!this.state.isRunning) {
      this.intervalID = setInterval(() => this.tick(), 1000);
    } else {
      clearInterval(this.intervalID);
    }
  };

  handleReset = () => {
    this.setState(prevState => {
      return {
        time: 0
      };
    });
  };

  render() {
    return (
      <div className="App">
        <h1>{this.state.time}</h1>
        <button onClick={this.handleTimer}>
          {this.state.isRunning ? "Stop" : "Start"}
        </button>
        <button onClick={this.handleReset}>Reset</button>
      </div>
    );
  }
}

https://codesandbox.io/s/simpletimer-znub7

Kristian Woods
Kristian Woods
23,414 Points

video: https://teamtreehouse.com/library/update-the-stopwatch-state-with-componentdidmount