title: ESLint in class with fat arrow using airbnb rules
body: <p>The following code located in a class that extends <code>React.Component</code></p>
  
  <pre><code>  nextState = () =&gt; {
      this.setState({
        state : this.state.state + 1
      });
    };
  </code></pre>
  
  <p>However ESLint with airbnb rules catches this and throws the following error:
  <code>error  Parsing error: Unexpected token =</code></p>
  
  <p>I would like to keep this syntax as it allows me to avoid binding <code>this</code> in the constructor.</p>