Book Image

Essential Angular

By : Victor Savkin, Jeff Cross
Book Image

Essential Angular

By: Victor Savkin, Jeff Cross

Overview of this book

Essential Angular is a concise, complete overview of the key aspects of Angular, written by two Angular core contributors. The book covers the framework's mental model, its API, and the design principles behind it. This book is fully up to date with the latest release of Angular. Essential Angular gives you a strong foundation in the core Angular technology. It will help you put all the concepts into the right places so you will have a good understanding of why the framework is the way it is. Read this book after you have toyed around with the framework, but before you embark on writing your first serious Angular application. This book covers concepts such as the differences between Just-In-Time (JIT) and Ahead-Of-Time (AOT) compilation in Angular, alongside NgModules, components and directives. It also goes into detail on Dependency Injection and Change Detection: essential skills for Angular developers to master. The book finishes with a look at testing, and how to integrate different testing methodologies in your Angular code.
Table of Contents (11 chapters)

Shallow testing

Testing component classes without rendering their templates works in certain scenarios, but not in all of them. Sometimes we can write a meaningful test only if we render a component's template. We can do that and still keep the test isolated. We just need to render the template without rendering the component's children. This is what is colloquially known as shallow testing.

Let's see this approach in action.

selector: 'talks-cmp',
template: '<talk-cmp *ngFor="let t of talks" [talk]="t"></talk-cmp>'
export class TalksCmp {
@Input() talks: Talk[];

This component simply renders a collection of TalkCmp.

Now let's look at its test.

import { async, ComponentFixture, TestBed } from '@angular/core/testing';
import { By } from '@angular/platform-browser';
import { DebugElement, NO_ERRORS_SCHEMA ...