title: Dependent nested observables
body: <p>I have two methods in which I'm doing some asynchronous operation but I don't want method 2 to execute until or unless the response from method 1 is positive, to indicate that we can proceed further.</p>
  <p>So, this is what I tried:</p>
  <p>Method 1:</p>
  <pre><code>private method1(): Observable&lt;any&gt; {
    return new Observable(() =&gt; {
      executingSomething();
      this.anotherSubscription.pipe(
        map(x =&gt; {
          console.log('Control is not reaching here');
          Also, how to indicate the caller that method2 can be executed?
          I can't return anything since I'm already returning the new Observable, above.
        })
      );
    });
  }
  </code></pre>
  <p>Caller:</p>
  <pre><code>concat(this.method1(), this.method2()).subscribe();
  </code></pre>
  <p>Issue: <code>anotherSubscription</code> is not even getting executed and I can't think of any way to pass a response from within <code>anotherSubscription</code> to the caller.</p>
  <p>I feel that I'm not using the observables in correct sense, here but can't seem to find anything anywhere.</p>