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Learning TypeScript 2.x - Second Edition
book

Learning TypeScript 2.x - Second Edition

by Remo H. Jansen
April 2018
Beginner content levelBeginner
536 pages
13h 21m
English
Packt Publishing
Content preview from Learning TypeScript 2.x - Second Edition

Dependency injection in Angular

Dependency injection in Angular requires us to define some unique identifiers using the InjectionToken class. Injection tokens are unique identifiers used to represent a type at runtime. The concept of InjectionToken in Angular is very similar to the concept of symbols in InversifyJS:

import { InjectionToken } from "@angular/core"; 
import { MovieService, ActorService } from "../interfaces"; 
 
export const ACTOR_SERVICE = new InjectionToken<MovieService>("ActorService"); 
export const MOVIE_SERVICE = new InjectionToken<MovieService>("MovieService"); 

After creating an InjectionToken, we must decorate the class that we wish to inject with the @injectable decorator, as demonstrated by the following code snippet: ...

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Publisher Resources

ISBN: 9781788391474Supplemental Content