Which of the following correctly declares an Angular service with @Injectable that is provided at the root injector?

easy📝 Syntax Q3 of 15

Angular - Services and Dependency Injection

Which of the following correctly declares an Angular service with @Injectable that is provided at the root injector?

A@Injectable({ providedIn: 'root' })\nexport class MyService {}

B@Injectable({ providedIn: root })\nexport class MyService {}

C@Injectable({ providedIn: 'app' })\nexport class MyService {}

D@Injectable()\nexport class MyService { providedIn = 'root'; }

Step-by-Step Solution

Solution:

Step 1: Understand the syntax for providedIn
The providedIn property must be a string literal specifying the injector scope, e.g., 'root'.
Step 2: Check each option
@Injectable({ providedIn: 'root' })\nexport class MyService {} uses the correct syntax with quotes around 'root'. @Injectable({ providedIn: root })\nexport class MyService {} misses quotes, which is invalid. @Injectable({ providedIn: 'app' })\nexport class MyService {} uses 'app' which is not a valid injector scope. @Injectable()\nexport class MyService { providedIn = 'root'; } incorrectly tries to assign providedIn inside the class body.
Final Answer:
@Injectable({ providedIn: 'root' })\nexport class MyService {} -> Option A
Quick Check:
Quotes around 'root' are mandatory [OK]

Quick Trick: Always use quotes around providedIn values [OK]

Common Mistakes:

MISTAKES

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