How to detect rxjs related memory leaks in Angular apps
Disclaimer: I'm the author of the tool I mention below.
This can be accomplished by keeping a list where new subscriptions are added to, and removing subscriptions from this list once it is unsubscribed.
The troublesome part is observing subscriptions. A straightforward way to achieve this is by monkey-patching the Observable#subscribe()
method, that is, replacing the Observable prototype method.
This is the overall approach of observable-profiler, a development tool which hooks into an Observable library (i.e rxjs) and prints leaking subscriptions in console.
A simple way to use the profiler is start tracking once the app is bootstraped, then stop tracking after a time:
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';import { Observable } from 'rxjs';import { setup, track, printSubscribers } from 'observable-profiler';setup(Observable);platformBrowserDynamic([]) .bootstrapModule(AppModule) .then(ref => { track(); window.stopProfiler = () => { ref.destroy(); const subscribers = track(false); printSubscribers({ subscribers, }); } });
Just call stopProfiler()
in devtools console once you want a report.