react/no-redundant-should-component-update

Rule category

Correctness.

What it does

Warns if you have shouldComponentUpdate defined when defining a class component that extends React.PureComponent.

Why is this bad?

While having shouldComponentUpdate will still work, it becomes pointless to extend React.PureComponent.

Examples

❌ Incorrect

class Foo extends React.PureComponent {
  shouldComponentUpdate() {
    // do check
  }
 
  render() {
    return <div>Radical!</div>;
  }
}
 
function Bar() {
  return class Baz extends React.PureComponent {
    shouldComponentUpdate() {
      // do check
    }
 
    render() {
      return <div>Groovy!</div>;
    }
  };
}

✅ Correct

class Foo extends React.Component {
  shouldComponentUpdate() {
    // do check
  }
 
  render() {
    return <div>Radical!</div>;
  }
}
 
function Bar() {
  return class Baz extends React.Component {
    shouldComponentUpdate() {
      // do check
    }
 
    render() {
      return <div>Groovy!</div>;
    }
  };
}
 
class Qux extends React.PureComponent {
  render() {
    return <div>Tubular!</div>;
  }
}

react/no-namespace react/no-render-return-value