40 lines
1.2 KiB
JavaScript
40 lines
1.2 KiB
JavaScript
// Convenience function to load polyfills and return a promise when it's done.
|
|
// If there are no polyfills, then this is just Promise.resolve() which means
|
|
// it will execute in the same tick of the event loop (i.e. near-instant).
|
|
|
|
function importBasePolyfills() {
|
|
return import(/* webpackChunkName: "base_polyfills" */ './base_polyfills');
|
|
}
|
|
|
|
function importExtraPolyfills() {
|
|
return import(/* webpackChunkName: "extra_polyfills" */ './extra_polyfills');
|
|
}
|
|
|
|
function loadPolyfills() {
|
|
const needsBasePolyfills = !(
|
|
window.Intl &&
|
|
Object.assign &&
|
|
Number.isNaN &&
|
|
window.Symbol &&
|
|
Array.prototype.includes
|
|
);
|
|
|
|
// Latest version of Firefox and Safari do not have IntersectionObserver.
|
|
// Edge does not have requestIdleCallback and object-fit CSS property.
|
|
// This avoids shipping them all the polyfills.
|
|
const needsExtraPolyfills = !(
|
|
window.IntersectionObserver &&
|
|
window.IntersectionObserverEntry &&
|
|
'isIntersecting' in IntersectionObserverEntry.prototype &&
|
|
window.requestIdleCallback &&
|
|
'object-fit' in (new Image()).style
|
|
);
|
|
|
|
return Promise.all([
|
|
needsBasePolyfills && importBasePolyfills(),
|
|
needsExtraPolyfills && importExtraPolyfills(),
|
|
]);
|
|
}
|
|
|
|
export default loadPolyfills;
|