title: Angular merge map for one after another http calls
body: <p>The <code>getDetails()</code> method returns an <code>Details[]</code> and with that array and there is a name property which I am passing to another http call</p>
  <pre><code>Details {
      name: String;
  </code></pre>
  <p>Details</p>
  <pre><code> getDetails()
       return this.https.get(&quot;/someValue&quot;) //this return Details[] from here I have to take  name property
  </code></pre>
  <p>return</p>
  <pre><code>{name : hello}
  </code></pre>
  <p>Information</p>
  <pre><code> getInformations(name:string) {
      return this.https.get(&quot;/anotherValue&quot;+&quot;?&quot;+ name)
   }
  </code></pre>
  <p>I am trying to first call <code>getDetails()</code> and pass the name property to</p>
  <pre><code>Information{
    Hieght:string
    age:string
  }
  
  getInformations()
  this.getDetails().pipe(mergeMap(x =&gt; 
   this.getInformations(x.name)).subscribe((inforamtionResults:Information[])=&gt;{
    console.log(&quot;Checking Informations&quot;+inforamtionResults.length) 
  </code></pre>
  <p>return</p>
  <pre><code> {height:160,
     age: 23
     }
  </code></pre>
  <p>This is not working as x value is an array. How do iterate the array and pass the array property as parameter?</p>