Add this to decorator to your RxJS Subscription's to unsubscribe them when ngOnDestroy is called

unsubscribe-decorator.ts

import { Subscription } from 'rxjs';

/**
 * Example:
 *
 * ```
 * @Unsubscribe()
 * public subscription: Subscription
 * ```
 *
 * or if you want another method to be called, use
 *
 * ```
 * @Unsubscribe('myCustomMethod')
 * public subscription: Subscription
 * ```
 */

export function Unsubscribe(on: string = 'ngOnDestroy'): PropertyDecorator {
  return function (target: Object, propertyKey: string | symbol) {
    const oldFunction: Function = target[on];
    replaceFunction(target, on, function () {
      if (oldFunction) {
        oldFunction.apply(this);
      }
      if (checkForSubscription(this[propertyKey])) {
        this[propertyKey].unsubscribe();
      }
    });
  };
}

function replaceFunction(target: any, name: string, newFunction: Function): void {
  Object.defineProperty(target, name, {
    value: newFunction
  });
}

function checkForSubscription(property: any): boolean {
  return property && property instanceof Subscription;
}