propTypes property

Allows usage of react.PropValidator functions to check the validity of a prop within the props passed to it.

Override with a custom implementation to easily add validation.

For performance reasons, propTypes is only checked in development mode.

Example of enforcing the length of a prop value:

mixin MyProps on UiProps {
  Object foo;
}

class MyComponent extends UiComponent2<MyProps> {
  @override
  get propTypes => {
    keyForProp((p) => p.foo): (props, info) {
      final length = props.foo?.length;
      if (length != 2) {
        return PropError.value(length, info.propName, 'must have a length of 2');
      }
      return null;
    },
  };
}

keyForProp - as shown in the example above - is a statically typed helper to get the string key for a prop.
The second argument (info) of the function used to return a value for the key contains metadata about the prop specified by the key.
- propName, componentName, location and propFullName are available.

Example of enforcing the relationship between two prop values:

mixin MyProps on UiProps {
  bool mustHaveAnotherPropValue;
  String anotherProp;
}

class MyComponent extends UiComponent2<MyProps> {
  @override
  get defaultProps => newProps()..someProp = false;

  @override
  get propTypes => {
    keyForProp((p) => p.mustHaveAnotherPropValue): (props, info) {
      if (props.mustHaveAnotherPropValue && props.anotherProp == null) {
        return PropError.combination(info.propName, 'anotherProp',
            'must have a non-null value when ${info.propName} is true.');
      }
      return null;
    },
  };
}

See: reactjs.org/docs/typechecking-with-proptypes.html#proptypes

Implementation

UiComponent2 class