title: Function inside render and class in reactjs
body: <p>I'm trying to learn reactjs and i have some uncertainties. I was refering react DOCS and some other tutorials and i saw functions are written inside render function and also inside class. What things should we do inside render function in react?</p>
  
  <p>1st way</p>
  
  <pre><code>class App extends Component {
  
      test(user) {
  
          return user.firstName;
      }
  
      render() {
  
          const user = {
              firstName: 'Harper',
              lastName: 'Perez'
          };
  
          return (
  
              &lt;div&gt;
  
                  &lt;h1&gt;{this.test(user)}&lt;/h1&gt;
  
              &lt;/div&gt;
          )
      }
  }
  </code></pre>
  
  <p>2nd way</p>
  
  <pre><code>class App extends Component {
  
         render() {
  
          const user = {
              firstName: 'Harper',
              lastName: 'Perez'
          };
  
          function test(user) {
  
              return user.firstName;
          }
  
          return (
  
              &lt;div&gt;
  
                  &lt;h1&gt;{test(user)}&lt;/h1&gt;
  
              &lt;/div&gt;
  
          )
  
      }
  }
  </code></pre>
  
  <p>Both this methods work. But i want to know what is the best method to do this? Most importantly i want to know what kind of things i can do inside render function.</p>
  
  <p>Thanks.</p>