Jquery Laravel 5.3：访问器值不进行JSON编码

我正在使用Laravel5.3和ajax制作一个crud应用程序。我在我的员工模型上使用访问器，如下所示：-

  class Employee extends Model
  {
  protected $table='employees';
  protected $primaryKey = 'id';


  protected $fillable=          ['name','designation','email','phone','address','bio','user_id'];

  public function getAvatarAttribute()
{
    if(file_exists(public_path("uploads/employee/employee_{$this->id}.jpg"))){
        return url("uploads/employee/employee_{$this->id}.jpg");
    }
    return url("images/employee_default.jpg");
}

EmployeeController.php：-

public function show(Request $request)
    {

      if($request->ajax()){
          $id = $request->id;
          $employee = Employee::find($id);
          return response()->json($employee);
      }

查看代码：-

<div class="col-sm-3">
        <img id="view_avatar" src="" alt="Avatar" class="img-thumbnail">
</div>

<p><b>Employee Name : </b><span id="view_ename" class="text-success"></span></p>
<p><b>Designation : </b><span id="view_designation" class="text-success"></span></p>
<p><b>Mobile No.: </b><span id="view_mobile" class="text-success"></span></p>
<p><b>Email: </b><span id="view_email" class="text-success"></span></p>
<p><b>Address : </b><span id="view_address" class="text-success"></span></p>

在这里，除了图像，所有数据都使用Ajax显示。 -当我

dd（$employee->avatar）时，在我的控制器中显示图像的url。
-但是在
console.log中（结果）输出关于化身没有任何内容

Console.log（结果）输出：-

我的问题是我哪里做错了？提前感谢。
您需要将属性添加到
$appends

class Employee extends Model {
    ...    
    /**
     * The accessors to append to the model's array form.
     *
     * @var array
     */
    protected $appends = ['avatar'];
    ...
}

address:"dhaka"
bio:"dhaka"
created_at:"2017-03-21 20:00:30"
designation:"partner"
email:"i.mossadek@gmail.com"
id:18
name:"Moloy"
phone:"01555555555"
updated_at:"2017-03-21 20:00:30"
user_id:26

class Employee extends Model {
    ...    
    /**
     * The accessors to append to the model's array form.
     *
     * @var array
     */
    protected $appends = ['avatar'];
    ...
}