refactor-app-component.md

Refactor App Component

We're going to perform a small refactoring. The app-root shouldn't have such a large template and all this logic. It should just call another component that will deal with that.

• Create a new component called list-manager:

ng g c list-manager

• Move all the code from app-root to list-manager.
• You can keep the title in app-root, and give it a nice value.
• Be careful not to change the list manager component's class name!

{% code-tabs %} {% code-tabs-item title="src/app/app.component.ts" %}

@Component({
  selector: 'app-root',
  template: `
    <h1>
      Welcome to {{ title }}!
    </h1>
  `,
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'My To Do List APP';
}

{% endcode-tabs-item %} {% endcode-tabs %}

{% code-tabs %} {% code-tabs-item title="src/app/list-manager/list-manager.component.ts" %}

import { Component, OnInit } from '@angular/core';
import { TodoItem } from '../interfaces/todo-item';

@Component({
  selector: 'app-list-manager',
  template: `
    <app-input-button-unit (submit)="addItem($event)"></app-input-button-unit>
  
    <ul>
      <li *ngFor="let todoItem of todoList">
        <app-todo-item [item]="todoItem"></app-todo-item>
      </li>
    </ul>
  `,
  styleUrls: ['./list-manager.component.css']
})
export class ListManagerComponent implements OnInit {
  todoList: TodoItem[] = [
    {title: 'install NodeJS'},
    {title: 'install Angular CLI'},
    {title: 'create new app'},
    {title: 'serve app'},
    {title: 'develop app'},
    {title: 'deploy app'},
  ];
  
  constructor() { }

  ngOnInit() {
  }
  
  addItem(title: string) {    
    this.todoList.push({ title });
  }
}

{% endcode-tabs-item %} {% endcode-tabs %}

• Call the new component from the app-root template:

{% code-tabs %} {% code-tabs-item title="src/app/app.component.ts" %}

  template: `
    <h1>
      Welcome to {{ title }}!
    </h1>
    
    <app-list-manager></app-list-manager>
  `,

{% endcode-tabs-item %} {% endcode-tabs %}

That's it! Now we can go on.