// class definition
var Category = {
  name: String,
  children: [Category]
}

// class instance
var category = {
  name: 'machine',
  children: [
    {
      name: 'automobile',
      children: [
        {
          name: 'car'
        },
        {
          name: 'truck'
        }
      ]
    },
    {
      name: 'computer'
    }
  ]
}