/* Data Service */
getMessages() {
  const dataArray = [];
  for (let index = 1; index < 25; index++) {
    const userName = this.faker.internet.userName();
    const content = this.faker.company.catchPhrase();
    const date = this.faker.date.recent();
    const data = { userName, content, date, index };
    dataArray.push(data);
  }
  return of(dataArray); // RxJS Observable
}