Jest Mock
Jest Mock is a feature of the Jest JavaScript testing framework that allows developers to create mock functions, modules, or objects to isolate and control dependencies during unit testing. It enables simulating behavior, tracking calls, and replacing real implementations with controlled test doubles to verify interactions and ensure tests are deterministic and focused on specific code units.
Developers should use Jest Mock when writing unit tests in JavaScript or TypeScript projects to isolate the code under test from external dependencies like APIs, databases, or other modules. It is essential for testing functions that rely on side effects, ensuring tests run quickly and reliably without making actual network calls or accessing real data, which improves test coverage and debugging efficiency.