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fix(service-worker): don't crash if SW not supported

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Currently a bug exists where attempting to inject SwPush crashes the
application if Service Workers are unsupported. This happens because
SwPush doesn't properly detect that navigator.serviceWorker isn't
set.

This change ensures that all passive observation of SwPush and
SwUpdate doesn't cause crashes, and that calling methods to perform
actions on them results in rejected Promises. It's up to applications
to detect when those services are not available, and refrain from
attempting to use them.

To that end, this change also adds an `isSupported` getter to both
services, so users don't have to rely on feature detection directly
with browser APIs. Currently this simply detects whether the SW API
is present, but in the future it will be expanded to detect whether
a particular browser supports specific APIs (such as push
notifications, for example).
This commit is contained in:
Alex Rickabaugh
2017-11-30 08:22:41 -08:00
parent 65f4fad801
commit b9a91a5e74
6 changed files with 82 additions and 7 deletions
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20
packages/service-worker/src/update.ts
View File

@ -9,9 +9,10 @@
import {Injectable} from '@angular/core';
import {Observable} from 'rxjs/Observable';
import {defer as obs_defer} from 'rxjs/observable/defer';
import {never as obs_never} from 'rxjs/observable/never';
import {map as op_map} from 'rxjs/operator/map';
import {NgswCommChannel, UpdateActivatedEvent, UpdateAvailableEvent} from './low_level';
import {ERR_SW_NOT_SUPPORTED, NgswCommChannel, UpdateActivatedEvent, UpdateAvailableEvent} from './low_level';
/**
@ -26,16 +27,33 @@ export class SwUpdate {
readonly activated: Observable<UpdateActivatedEvent>;
constructor(private sw: NgswCommChannel) {
if (!sw.isEnabled) {
this.available = obs_never();
this.activated = obs_never();
return;
}
this.available = this.sw.eventsOfType('UPDATE_AVAILABLE');
this.activated = this.sw.eventsOfType('UPDATE_ACTIVATED');
}
/**
* Returns true if the Service Worker is enabled (supported by the browser and enabled via
* ServiceWorkerModule).
*/
get isEnabled(): boolean { return this.sw.isEnabled; }
checkForUpdate(): Promise<void> {
if (!this.sw.isEnabled) {
return Promise.reject(new Error(ERR_SW_NOT_SUPPORTED));
}
const statusNonce = this.sw.generateNonce();
return this.sw.postMessageWithStatus('CHECK_FOR_UPDATES', {statusNonce}, statusNonce);
}
activateUpdate(): Promise<void> {
if (!this.sw.isEnabled) {
return Promise.reject(new Error(ERR_SW_NOT_SUPPORTED));
}
const statusNonce = this.sw.generateNonce();
return this.sw.postMessageWithStatus('ACTIVATE_UPDATE', {statusNonce}, statusNonce);
}