Another way to type javascript objects

object_types.js

/**
 * Checks the data type of property and throws a TypeError if it's invalid.
 *
 * Usage:
 *
 * function test(options = {}) {
 *   checkObjectTypes(options, {'a':'String', 'b':'Number', 'c':'Array'});
 * }
 *
 * @param {Object} obj
 * @param {Object} types
 */
export default function checkObjectTypes(obj, types = {}) {
    for (let prop in types) {
        if (obj[prop] === undefined
            || (obj[prop].constructor.name !== types[prop] || Object.prototype.toString.call(obj[prop]) === -1)) {
            throw new TypeError(`prop "${prop}" must be of type "${types[prop]}"`);
        }
    }
}