React components describe an independent and reusable piece of UI. To define it one can declare a function (functional component) or a class (class component). When implementing a class component, a render method is required to return the DOM structure, typically with JSX syntax.

When writing the render method in a component it is easy to forget to return the JSX content, which means the component will render nothing. Thus having a render method without a single return statement is usually a mistake. If it’s required that the component renders to nothing, the method should return null.

Noncompliant Code Example

const React = require('react');
class App extends React.Component {
  render() {
    <div>Contents</div>;
  }
}

Compliant Solution

const React = require('react');
class App extends React.Component {
  render() {
    return <div>Contents</div>;
  }
}

See