ขอบเขต single เทียบกับ factory

Koin gives you two main definition keywords: single and factory. They differ in one thing, how often Koin builds the object.

A single is created once and shared everywhere. Every part of your app that asks for it receives the very same object. 🔁

A factory builds a brand new instance on every request. Nothing is cached, so two callers never share the same object.

Use single for things that hold state or are expensive to build, like a repository, an HTTP client, or a database driver.

Reach for factory when each caller wants its own short-lived object, such as a stateless use case or a one-shot mapper.

A single is not built when you declare it. Koin creates it the first time something actually asks for it, then keeps it around.

Need a single ready at startup instead of on first use? Add createdAtStart so Koin builds it the moment the container starts.

A single repository can depend on a factory mapper. Koin happily mixes scopes, building the factory fresh inside the long-lived single.

If you make something single by mistake, callers may share state you meant to keep private, a classic source of subtle multiplatform bugs.

Here a long-lived repository and a fresh use case live side by side, each scoped to match how it is used.

When unsure, start with single. Most app-wide services want one instance, and you can switch to factory the moment you truly need fresh objects.

Pick the right scope behavior.

You learned that single shares one instance while factory builds a new one each time. Pick single for shared services, factory for short-lived helpers. 👍