Is it possible to check prop types as case insensitive on React prop-types?

Question

I wonder if there is a way to check prop types case insensitive in React. Basically, the solution should replace the following code. As far as I checked, there is no solution on the official documentation of prop-types.

Brand.propTypes = {
    name: PropTypes.oneOf([
        'google',
        'Google',
        'GOOGLE'
    ])
}

Answer 1

From the React PropTypes Docs:

// You can also specify a custom validator. It should return an Error
// object if the validation fails. Don't `console.warn` or throw, as this
// won't work inside `oneOfType`.
customProp: function(props, propName, componentName) {
  if (!/matchme/.test(props[propName])) {
    return new Error(
      'Invalid prop `' + propName + '` supplied to' +
      ' `' + componentName + '`. Validation failed.'
    );
  }
},

So with this in mind, you could write your own custom matcher like this that takes care of your requirement:

const matchesCaseInsensitiveString = (matchingString) => {
  const matchingStringLower = matchingString.toLowerCase();
  return (props, propName, componentName) => {
    const propValue = props[propName];
    if (typeof propValue !== "string" || props[propName].toLowerCase() !== matchingStringLower) {
      return new Error('Expected ' + matchingStringLower + ' but got ' + propValue);
    }
  }
}

// example
const propTypes = {
  google: matchesCaseInsensitiveString('GOOGLE'),
  yahoo: matchesCaseInsensitiveString('Yahoo'),
};

const props = {
  google: 'google',
  yahoo: 'Bing',
};

console.log(
  propTypes.google(props, 'google', 'MyFakeComponent')
); // won't return an error

console.log(
  propTypes.yahoo(props, 'yahoo', 'MyFakeComponent')
); // will return an error

This is a bit rough (it defaults to an .isRequired type matching check and has a pretty rudimentary warning) but you get the rough idea of how this can be accomplished.