[Solved] Which is the correct way to make an Angular service a singleton using the @Injectable decorator? - Ans: @Injectable({ providedIn: 'root' }) | Angular

Angular - Services and Dependency Injection

Which is the correct way to make an Angular service a singleton using the @Injectable decorator?

A@Injectable({ scope: 'singleton' })

B@Injectable({ providedIn: 'root' })

C@Injectable({ singleton: true })

D@Injectable({ providedIn: 'component' })

Step-by-Step Solution

Solution:

Step 1: Recall Angular service singleton syntax
Angular uses providedIn: 'root' to provide a singleton service at the app root level.
Step 2: Check each option's validity
Only @Injectable({ providedIn: 'root' }) uses the correct syntax. Others are invalid or do not exist in Angular.
Final Answer:
@Injectable({ providedIn: 'root' }) -> Option B
Quick Check:
Singleton service = providedIn: 'root' [OK]

Quick Trick: Use providedIn: 'root' for singleton services [OK]

Common Mistakes:

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Which is the correct way to make an Angular service a singleton using the @Injectable decorator?