todo-list.component.ts

todos: TodoViewModel[] = [];

  loadTodos() {
    this.todoService.getTodos().subscribe(response => {
      this.todos = [];
      response.docs.forEach(value => {
        const data = value.data();
        const id = value.id;
        const todo: TodoViewModel = {
          id: id,
          title: data.title,
          description: data.description,
          done: data.done,
          lastModifiedDate: data.lastModifiedDate.toDate()
        };

        this.todos.push(todo);
      });
    });
}