migracode clock ticking

clock.js

import React, { Component } from "react";
import ReactDOM from "react-dom";

class Time extends Component {
  constructor(props) {
    super(props);
    this.state = {
      date: new Date(),
      count: 0
    };
  }

  componentDidMount() {
    this.start();
  }

  componentWillUnmount() {
    this.pause();
  }

  pause = () => {
    clearInterval(this.timerId);
  };

  start = () => {
    this.timerId = setInterval(this.tick, 1000);
  };

  tick = () => {
    console.log("tick", this.state.count);

    this.setState(previousState => {
      return {
        date: new Date(),
        count: previousState.count + 1
      };
    });
  };

  render() {
    return (
      <div>
        {this.state.date.toLocaleTimeString()}
        <button onClick={this.pause}>pause</button>
        <button onClick={this.start}>start</button>
      </div>
    );
  }
}

class Clock extends Component {
  constructor(props) {
    super(props);
    this.state = { isShowingClock: true };
  }

  toggle = () => {
    this.setState(previousState => {
      return { isShowingClock: !previousState.isShowingClock };
    });
  };

  render() {
    return (
      <div>
        {this.state.isShowingClock ? <Time /> : null}
        <button onClick={this.toggle}>Toggle time</button>
      </div>
    );
  }
}

ReactDOM.render(<Clock />, document.getElementById("root"));