service-worker.patch

4c4,39
< 
---
>   const waitUntil = ExtendableEvent.prototype.waitUntil;
>   const respondWith = FetchEvent.prototype.respondWith;
>   const promisesMap = new WeakMap();
> 
>   ExtendableEvent.prototype.waitUntil = function(promise) {
>     const extendableEvent = this;
>     let promises = promisesMap.get(extendableEvent);
> 
>     if (promises) {
>       promises.push(Promise.resolve(promise));
>       return;
>     }
> 
>     promises = [Promise.resolve(promise)];
>     promisesMap.set(extendableEvent, promises);
> 
>     // call original method
>     return waitUntil.call(extendableEvent, Promise.resolve().then(function processPromises() {
>       const len = promises.length;
> 
>       // wait for all to settle
>       return Promise.all(promises.map(p => p.catch(()=>{}))).then(() => {
>         // have new items been added? If so, wait again
>         if (promises.length != len) return processPromises();
>         // we're done!
>         promisesMap.delete(extendableEvent);
>         // reject if one of the promises rejected
>         return Promise.all(promises);
>       });
>     }));
>   };
> 
>   FetchEvent.prototype.respondWith = function(promise) {
>     this.waitUntil(promise);
>     return respondWith.call(this, promise);
>   };