title: Why doesn't my state update in React.js
body: <p>I don't understand why my state isn't updating in this code. I reviewed an answer <a href="https://stackoverflow.com/questions/34716581/why-isnt-my-state-updating">here</a> but doesn't seem to answer my question b/c I only have one component to bind to.</p>
  
  <pre><code>import React from 'react';
  import ReactDOM from 'react-dom';
  
  class App extends React.Component {
      constructor() {
          super();
          this.state={
              headline: 'this is headline state',
              cat: 25
          }
      }
  
      update(e) {
          this.setState=({headline: e.target.value})
      }
  
      render() {
          let headline=this.state.headline
          return (
              &lt;div&gt;
                  &lt;input type="text"
                  onChange={this.update.bind(this)} /&gt;
                  &lt;h1&gt;{headline}&lt;/h1&gt;
              &lt;/div&gt;
          );
      }
  }
  
  App.propTypes = {
      headline: React.PropTypes.string,
      cat: React.PropTypes.number
  }
  
  ReactDOM.render(
      &lt;App /&gt;,
      document.getElementById('app')
      );
  </code></pre>