I cannot do Array (in JSON) in Typescript

Question

Below is the Array I need:

[
   {
      "id":1,
      "nome":"LESPAUL",
      "validade":1525568400000,
      "dataGerada":1525914000000,
      "status":true,
      "itens":[
         {
            "cliente":{
               "id":1,
               "login":"gabriel",
               "senha":"123",
               "tipoDeLogin":1,
               "telefone":"99916-2410",
               "endereco":"Zetete Tororo 25",
               "nome":"Gabriel Sereno",
               "cpf":"12312312312"
            }
         }
      ]
   }
]

Below is the Array that is produced:

{
  "id": 1,
  "nome": "LESPAUL",
  "validade": 1525568400000,
  "dataGerada": 1525914000000,
  "status": true,
  "itens": [
    {
      "id": 1,
      "login": "gabriel",
      "senha": "123",
      "tipoDeLogin": 1,
      "telefone": "99916-2410",
      "endereco": "Zetete Tororo 25",
      "nome": "Gabriel Sereno",
      "cpf": "12312312312"
    }
  ]
}

You can see that I want Array Items be an Array of Clients, only it prints the JSON without the client class, follows the code I made:

import { Component } from '@angular/core';
import { IonicPage, NavController, NavParams, ModalController } from 'ionic-angular';
import { ApiProvider } from '../../../providers/api/api';
import { LoaderProvider } from '../../../providers/loader';
import { ToastProvider } from '../../../providers/toast';

@IonicPage()
@Component({
  selector: 'page-codigo',
  templateUrl: 'codigo.html',
})
export class CodigoPage {

  listClientes: any;
  listCodigos: any;
  codigoMarcado: any;
  marca: boolean = true;

  constructor(public navCtrl: NavController,
    public toast: ToastProvider,
    public api: ApiProvider,
    public modalCtrl: ModalController,
    public loader: LoaderProvider,
    public navParams: NavParams) {
  }

  ionViewDidLoad() {
    this.loader.show();

    this.api.obter("clientes/codigos").then(data => {
      this.loader.hide();
      this.listClientes = data;
    });

    this.listarCodigos();
  }

  listarCodigos() {
    this.loader.show();

    this.api.obter("codigos", true).then(data => {
      this.listCodigos = data;
      this.loader.hide();
    })
  }

  selecionarTodos() {
    this.listClientes.forEach(data => {
      data.marcado = this.marca;
    })

    this.marca = !this.marca;
  }

  adicionar() {
    let modal = this.modalCtrl.create("CrudCodigoPage");

    modal.present();

    modal.onDidDismiss(data => {
      this.listarCodigos();
    })
  }

  enviarCodigo() {
    this.loader.show();

    let auxList = this.codigoMarcado.itens;

    this.codigoMarcado.itens = new Array<Cliente>();

    if (auxList != null) {
      this.listClientes.concat(auxList);
    }

    this.listClientes.forEach(data => {
      if (data.marcado) {

        let bool = false;
        for (let aux of auxList) {
          if (aux.id == data.id) {
            bool = true;
          }
        }

        if (!bool) {
          delete (data.marcado);
          this.codigoMarcado.itens.push(new Cliente(data.id, data.login, data.senha, data.tipoDeLogin, data.telefone, data.endereco, data.nome, data.cpf));
        }

      }
    });

    // console.log(this.codigoMarcado)

    this.api.put("codigos", this.codigoMarcado).then(data => {
      this.toast.show("Enviado os códigos com sucesso!");
      this.loader.hide();
    });
  }

}

export class Cliente {
  id: number;
  login: string;
  senha: string;
  tipoDeLogin: string;
  telefone: string;
  endereco: string;
  nome: string;
  cpf: string;

  constructor(id: number,
    login: string,
    senha: string,
    tipoDeLogin: string,
    telefone: string,
    endereco: string,
    nome: string,
    cpf: string) {

    this.id = id;
    this.login = login;
    this.senha = senha;
    this.tipoDeLogin = tipoDeLogin;
    this.telefone = telefone;
    this.endereco = endereco;
    this.nome = nome;
    this.cpf = cpf;
  }
}