title: update doesn't work with setState in react
body: <p>Try to update a state of array using map of es6, got some issue.. What's wrong with this code?</p>
  
  <pre><code>this.setState({
    drinks: this.state.drinks.map(o =&gt; {
      if (o === this.state.newDrink) {
        return this.state.newDrink;
      }
      return o;
    })
  });
  </code></pre>
  
  <p>where drinks is an array. My add functionality is fine but not for update, I think something is wrong above?</p>
  
  <p>My demo <a href="https://codesandbox.io/s/nk6qo8krvm" rel="nofollow noreferrer">https://codesandbox.io/s/nk6qo8krvm</a></p>