title: Is it good to call subscribe inside subscribe?
body: <p>I need to pass three data to one function from three different APIs:</p>
  
  <pre class="lang-js prettyprint-override"><code>this.service.service1().subscribe( res1 =&gt; {
    this.service.service1().subscribe( res2 =&gt; {
      this.service.service1().subscribe( res3 =&gt; {
        this.funcA(res1, res2, res3);
    });
    });
  });
  </code></pre>
  
  <p>Is it a good practice to subscribe inside a subscribe?</p>