RefactorDependency

To refactor hard-coded dependencies like fetch or localStorage for unit testing, replace them with injectable abstractions such as constructor parameters or adapters. This isolates one dependency type per iteration to minimize risk while keeping public APIs unchanged and tests green.

The safest way to introduce dependency injection in a TypeScript project is limiting changes to one dependency type and at most two modules. By preferring constructor or function parameter injection, you ensure predictable refactoring with minimal call-site changes and preserved behavior.

Yes, you can swap concrete dependencies with injected abstractions without altering public APIs by using adapters or DI contexts. This approach decouples code from specific implementations while preserving the external interface and keeping existing tests green.

Dependency injection refactoring limits changes to at most two modules per iteration. This narrow scope ensures predictable refactoring in real-world projects by minimizing risk, preserving behavior, and making code reviews easier while updating imports and constructor calls.

You should not use constructor parameter injection when refactoring scope exceeds one dependency type or two modules. Broad changes risk breaking public APIs and test suites; this approach requires minimal call-site updates and isolated adapters to maintain predictable behavior.