Track all observable subscriptions

_Track RxJs subscriptions.md

Exmaple usage:

• Add this piece of code in your angular application's main.ts, above the bootstrap call
• Execute subscriptions.clear() in the console, because a lot of subscriptions are created at bootstrap time
• Trigger the actions you want to investigate
• Copy the subscriptions map to prevent changes while you're investigating
• Investigate

track-subscriptions.ts

import {Observable, Subscription} from 'rxjs';

declare const subscriptions: Map<Observable<any>, Subscription[]>;
(window as any).subscriptions =  new Map<Observable<any>, Subscription[]>();

Observable.prototype.subscribe = (function (_super) {
  return function(this: Observable<any>, ...args: any[]) {
    const subscription = _super.apply(this, args)
    const list = subscriptions.get(this);

    if (list != null) {
      list.push(subscription);
    } else {
      subscriptions.set(this, [subscription]);
    }

    return subscription;
  };
})(Observable.prototype.subscribe);