title: How to store multiple checkbox values in reactive form in angular2?
body: <p>I am working on angular2 application and getting problem in storing values of multiple check boxes in form field.</p>
  
  <p>Type script</p>
  
  <pre><code>form : FormGroup;
  cities = ["Mohali", "Chandigarh", "Ludhiana", "Amritsar"];
  zip_codes = ["282001", "456123", "123456", "140412"];
  
  constructor(private formBuilder : FormBuilder)
  {
      this.form = this.formBuilder.group({
         cities   : this.formBuilder.array(["Mohali", "Amritsar"]),
         zip_codes : this.formBuilder.array(["456123"])
      });
  }
  </code></pre>
  
  <p>HTML </p>
  
  <pre><code>&lt;div *ngFor="let city of cities"&gt;
      &lt;input type="checkbox" formControlName="cities" value="city"&gt;
      &lt;span&gt;{{city}}&lt;/span&gt;
  &lt;/div&gt;
  
  &lt;div *ngFor="let zipCode of zip_codes"&gt;
      &lt;inbput type="checkbox" formControlName="zip_codes" value="zipCode"&gt;
       &lt;span&gt;{{zipCode}}&lt;/span&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I want to store checked cities and zip_codes in form field and when I have default values in form field then the values are in array will be checked automatically.</p>