React Lifecycle Methods

LifecycleMethods.js

  componentDidMount() {
    this.timerID = setInterval(() => this.tick(), 1000 );
  }
  componentDidUpdate(prevProps, prevState) {
  // Typical usage (don't forget to compare props):
  if (this.props.userID !== prevProps.userID) {
    this.fetchData(this.props.userID);
  }
}
  componentWillUnmount() {
        clearInterval(this.timerID);
  }