title: Synchronizing nested subscribe in angular2
body: <p>I have the following code which logs : <code>"foo2"</code> and then <code>"foo1"</code>: </p>
  
  <pre><code>a() {
    b().then(() =&gt; {
       console.log("foo2")
    })
  }
  
  b() {
     return webServiceCall().do(() =&gt; {
        webServiceCall2().subscribe(() =&gt; {
           console.log("foo1")      
        })
     }) 
  }
  </code></pre>
  
  <p>I would like to be sure that my <code>foo1</code> appears before my <code>foo2</code>.</p>
  
  <p>How could I solve this issue ? Thanks !</p>