app/javascript/flavours/glitch/util/load_polyfills.js

   1 // Convenience function to load polyfills and return a promise when it's done.
   2 // If there are no polyfills, then this is just Promise.resolve() which means
   3 // it will execute in the same tick of the event loop (i.e. near-instant).
   4
   5 function importBasePolyfills() {
   6   return import(/* webpackChunkName: "base_polyfills" */ './base_polyfills');
   7 }
   8
   9 function importExtraPolyfills() {
  10   return import(/* webpackChunkName: "extra_polyfills" */ './extra_polyfills');
  11 }
  12
  13 function loadPolyfills() {
  14   const needsBasePolyfills = !(
  15     Array.prototype.includes &&
  16     HTMLCanvasElement.prototype.toBlob &&
  17     window.Intl &&
  18     Number.isNaN &&
  19     Object.assign &&
  20     Object.values &&
  21     window.Symbol
  22   );
  23
  24   // Latest version of Firefox and Safari do not have IntersectionObserver.
  25   // Edge does not have requestIdleCallback and object-fit CSS property.
  26   // This avoids shipping them all the polyfills.
  27   const needsExtraPolyfills = !(
  28     window.IntersectionObserver &&
  29     window.IntersectionObserverEntry &&
  30     'isIntersecting' in IntersectionObserverEntry.prototype &&
  31     window.requestIdleCallback &&
  32     'object-fit' in (new Image()).style
  33   );
  34
  35   return Promise.all([
  36     needsBasePolyfills && importBasePolyfills(),
  37     needsExtraPolyfills && importExtraPolyfills(),
  38   ]);
  39 }
  40
  41 export default loadPolyfills;