react/no-redundant-should-component-update

React.PureComponent already decides when to render again by comparing the old and new props and state. If you write your own shouldComponentUpdate, it replaces that comparison, so extending PureComponent no longer does anything. Keep one of the two.

Configure

Off by default. To turn it on:

[lint.rules]
"react/no-redundant-should-component-update" = "error" # or "warn"

Examples

Reported:

class Price extends React.PureComponent {
  shouldComponentUpdate(nextProps) {
    return nextProps.amount !== this.props.amount;
  }

  render() {
    return <span>{this.props.amount}</span>;
  }
}

Not reported:

class Price extends React.PureComponent {
  render() {
    return <span>{this.props.amount}</span>;
  }
}

class Total extends React.Component {
  shouldComponentUpdate(nextProps) {
    return nextProps.amount !== this.props.amount;
  }

  render() {
    return <strong>{this.props.amount}</strong>;
  }
}