title: Convert Json String to json Arrays in angular 6
body: <p>Hi I want to convert the RestController Response which is in Json String to json array here is my json array sting which i have printed in console.</p>
  
  <pre><code>'{"Impressions":["Budget","CTR","Campaign","Campaign state","Clicks","Conv. rate"],"Clicks":["Budget","CTR","Campaign","Campaign state","Clicks","Conv. rate"],"Revenue":["Budget","CTR","Campaign","Campaign state","Clicks","Conv. rate"]}'
  </code></pre>
  
  <p>I want to convert it to json array so that i can iterate it,</p>
  
  <p>My requirement is to iterate the array and print key as label and value as slect options</p>
  
  <p>Example:</p>
  
  <p>Impression as label and "Budget","CTR","Campaign","Campaign state","Clicks","Conv. rate" as select options.</p>
  
  <p>Here is my code for iteration</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;div&gt;
     &lt;form *ngFor ="let map of mapper"&gt;
        &lt;mat-form-field&gt;
           &lt;mat-select placeholder="{{map}}"&gt;
              &lt;!--&lt;mat-option&gt;None&lt;/mat-option&gt;--&gt;
               &lt;mat-option *ngFor="let option of map"  [value]="option"&gt; 
                  {{option}}
               &lt;/mat-option&gt;
           &lt;/mat-select&gt;
        &lt;/mat-form-field&gt;
      &lt;/form&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>my .ts class</p>
  
  <pre class="lang-js prettyprint-override"><code>this.clientService.getHeaders().subscribe(
        (res) =&gt; {
            console.log(res);
            let resSTR = JSON.stringify(res);
            let resJSON = JSON.parse(resSTR);
            this.mapper=Array.of(resJSON._body);
            console.log(this.mapper);
            this.ismapped=false;
        }
  );
  </code></pre>