A simple library for polyfilling missing functionality in older browsers

polyfill.js

/**
 * Polyfills a property on the given object. If the object already has the
 * property, no action is taken.
 *
 * @param {?} object
 *        Object whose property should be polyfilled.
 * @param {String} name
 *        Name of the property to polyfill.
 * @param {?} value
 *        Value for the property.
 * @param {Boolean} [force=false]
 *        If true, the change will be forcably applied. If false, the change
 *        will only be applied if the property isn't a match.
 */
function polyfill(object, name, value, force) {

    if (force || typeof object[name] !== typeof value) {

        Object.defineProperty(object, name, {
            value: value,
            configurable: true,
            enumerable: false,
            writable: true
        });

    }

}

/**
 * Polyfills multiple properties onto one or more objects.
 *
 * @param {Array<?>|?} objects
 *        Either the object to polyfill or an array of objects to polyfill.
 * @param {Object} methods
 *        Methods to polyfill.
 * @param {Boolean} [force=false]
 *        If true, the changes will be forcably applied. If false, the changes
 *        will only be applied if the property isn't a match.
 */
function polyfillAll(objects, methods, force) {

    if (!Array.isArray(objects) || objects === Array.prototype) {
        objects = [objects];
    }

    objects.forEach(function (object) {

        Object
            .keys(methods)
            .forEach(function (key) {
                polyfill(object, key, methods[key], force);
            });

    });

}

using polyfill.js

// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/entries#Polyfill
polyfill(Object, "entries", function (object) {

    return Object.keys(object).map(function (key) {
        return [key, object[key]];
    })

});

// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes
polyfillAll([
    String.prototype,
    Array.prototype
], {

    includes: function (search) { // .length = 1
        return this.indexOf.apply(this, arguments) > -1;
    }

});

Converted into a git repo:
https://github.com/james-jlo-long/polyfill