Eslint-plugin-react: What is the best way of defining optional event handlers in propTypes?

[alisabzevari]

I have a component that has an onChange event. Providing the event handler for this component is optional. I have defined the propTypes as follows:

Cmp.propTypes = {
  onChange: React.PropTypes.func
}

But I will get the react/require-default-props eslint error.
My question is that how can I define a propType of Function | undefined?

[petersendidit]

The rule is checking if there is a default prop for non required props.

You can set a noop function as the default:

Cmp.defaultProps = {
    onChange: () => {}
}

[ljharb]

You can also set null or undefined as the default, since all non-required props allow those.