SomePropType.js

/**
* Custom PropType for checking multiple PropTypes. 
*
* Returns an error if the prop does not pass one of the PropType checks.
* Sourced from: http://stackoverflow.com/a/31169012
*
* @param {mixed} any valid React PropType (element|string|arrayOf|shape|...)
*
* @returns {error} returns an error if all fail
*/
export const somePropType = (...types) => {
  return (...args) => {
    // PropTypes are functions that return null if they pass and an error if they fail.
    // So, by checking if at least one of the functions returned null, then we know that
    // one of the PropType checks passed.
    
    // If all are non-null, then we want to log both of throw an error with both of those messages.
    
    const errors = types.map((type) => type(...args));
    const passed = errors.some(resp => resp === null);

    if (!passed) {
      // Didn't pass any of the PropType checks.
      // Collect the error messages and join them together.
      const message = errors.map((e) => e.message).join('\n');

      return new Error(message);
    }
    return;
  }
}

// Usage
import React from 'react';
import { somePropType } from './SomePropType.js';
const { element, arrayOf } = React.PropTypes;
MyComponent.propTypes = {
  // Ensures anImportantValue is either an element or an array of elements.
  anImportantValue: somePropType(element, arrayOf(element))
};