title: set initial react component state in constructor or componentWillMount?
body: <p>In react components is it preferred to set the initial state in the constructor() or componentWillMount()?</p>
  
  <pre><code>export default class MyComponent extends React.Component{
    constructor(props){
      super(props);
      this.setState({key: value});
    }
  }
  </code></pre>
  
  <p>or</p>
  
  <pre><code>export default class MyComponent extends React.Component{
    componentWillMount(props){
      this.setState({key: value});
    }
  }
  </code></pre>