What is spyOn() in Jasmine, and how do you use it in Angular tests?

Short answer: spyOn() creates a spy on a method, allowing you to track calls and override behavior.

Example code

spyOn(service, 'getData').and.returnValue(of(['mock data'])); Useful for mocking service methods and verifying interactions.

Real-world example (ShopNest)

ShopNest admin can be built in Angular with modules/components, services for API calls, and reactive forms for product edit.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.