title: Spread operator in React .setState()
body: <p>Given the following snippet extracted from a React class component:</p>
  
  <pre><code>constructor(props) {
      super(props)
      this.state = { active: true }
    }
  
    deactivate = () =&gt; {
      this.setState({ ...this.state, active: false })
    }
  </code></pre>
  
  <p>What is the aim of the spread operator into the stopCounter() method? The application also works removing it:</p>
  
  <pre><code>  deactivate = () =&gt; {
      this.setState({ active: false })
    }
  </code></pre>