old react and IE11 polyfills - reactjs

Question

Im running React 0.13 and cant upgrade (long story). Cant use Babel-Polyfill.
I need to make the application IE11 compatable so I need to implement a lot of polyfills.
How do I or can I include the polyfills in a singular file and make that file globally visible?
I have a file containing just the polyfills ( like this one )
But im unsure how to include it to just be visible globally by default.
if (typeof Object.assign != 'function') {
Object.assign = function(target) {
'use strict';
if (target == null) {
throw new TypeError('Cannot convert undefined or null to object');
}
target = Object(target);
for (var index = 1; index < arguments.length; index++) {
var source = arguments[index];
if (source != null) {
for (var key in source) {
if (Object.prototype.hasOwnProperty.call(source, key)) {
target[key] = source[key];
}
}
}
}
return target;
};
}

Answer 1

you can implement a function that wraps all the polyfills and import it wherever you need it.
export function loadCustomPolyfills() {
if (typeof Object.assign != 'function') {
Object.assign = function(target) {
..
};
}
//other polyfills
}
and in you entry point file, at the beginning
import { loadCustomPolyfills } from './custom-polyfills';
loadCustomPolyfills();