title: How use formData.append for a array in typescript
body: <p>Hi i want to send a form to my endpoint Profile, my problem is in the field user:{}, because i can't find the way to put my array into this field.</p>
  
  <p>this are the field in my endpoint:</p>
  
  <pre><code>{
    "id": 4,
    "ci": "123456",
    "photo": "http://127.0.0.1:8000/media/profiles/12809632_10208569440535095_617453747387788113_n_zAUAVMf.jpg",
    "phone_number": "+59177621589",
    "user": {
      "id": 5,
      "username": "sdanderson",
      "first_name": "ssss",
      "last_name": "ssss"
    },
    "experience": "null",
    "typeskill": [
      {
        "id": 1,
        "skill_name": "developer"
      }
    ]
  }
  </code></pre>
  
  <p>And here is my service for make a PUT request:</p>
  
  <pre><code>putProfile(id:string,token:string,body:any,files:any):Observable&lt;Profile&gt;{
  
  //save data to send to the endpoint for update
      let formData: FormData = new FormData();
  
      for (let file of files) {
          formData.append('photo', file);
      }
      formData.append('ci',body['ci']);  
      formData.append('phone_number', body['phone_number']); 
      formData.append('experience',body['experience']);
      formData.append('user',body['user']);//here i have inside the fields: body['user'].id,body['user'].first_name,body['user'].last_name
  
  
  
  
  
      //include header
      let headers = new Headers();
      headers.append('Accept', 'application/json');
      headers.append("Authorization","Token "+ token);
  
      return this.http.put(this.api+"profile/"+id+'/',formData,{headers})
          .map(this.extractData)
          .catch(this.handleError);
  }
  </code></pre>