title: ESLint - no-unused-expressions in ReactJS
body: <p>Getting a ESLint error when copiling with babel:</p>
  
  <ul>
  <li><p>Line 28:  Expected an assignment or function call and instead saw an expression  no-unused-expressions</p></li>
  <li><p>Line 29:  Expected an assignment or function call and instead saw an expression  no-unused-expressions</p></li>
  </ul>
  
  <p>Any idea how to get rid of these whilst making my timer still work as intended? Or have you got a better way of me doing my timer?</p>
  
  <pre><code>class RequestTimer extends Component {
      constructor(props) {
          super(props);
  
          this.state = {
              seconds: 0,
              minutes: 0,
              hours: 0
          }
  
          this.getTime = this.getTime.bind(this);
      }    
  
      getTime() {
          let second = this.state.seconds
          let minute = this.state.minutes;
          let hour = this.state.hours; 
  
          this.state.seconds % 59 === 0 &amp;&amp; this.state.seconds !== 0 ? minute += 1:null;
          this.state.minutes % 59 === 0 &amp;&amp; this.state.seconds % 59 === 0 &amp;&amp; this.state.minutes !== 0 ? (hour += 1, minute = 0):null;
  
          this.setState({
              seconds: second +=1,
              minutes: minute,
              hours: hour
          })
      }
  
      componentDidMount() {
          this.timer = setInterval(this.getTime, 1000)
      }
  
      render() {
          return (
              &lt;TimerContainer&gt;
                  &lt;h2&gt;Last Request:&lt;/h2&gt;
                  &lt;p&gt;{this.state.hours}h {this.state.minutes}m {this.state.seconds % 60}s&lt;/p&gt;                
              &lt;/TimerContainer&gt;
          )
      }
  }
  </code></pre>