polyfill-loader.js

import Promise from 'promise'

export const loadPolyfills = () => {
  return new Promise((resolve) => {
    let promises = []

    if ( !global.fetch ) {
      promises.push(new Promise((subResolve) => {
        require(['whatwg-fetch'], subResolve)
      }))
    }

    if ( !Object.assign ) {
      promises.push(new Promise((subResolve) => {
        require(['./object-assign-polyfill'], subResolve)
      }))
    }

    if ( promises.length ) {
      Promise.all(promises).then(resolve)
    } else {
      resolve()
    }
  });
}


/*

Elsewhere in your app:

const renderApp = () => {
  // Render your application
}

import { loadPolyfills } from './polyfill-loader'
loadPolyfills().then(renderApp);