ts-best-practices-functional

Refactor or author TypeScript using a functional doctrine: factories over classes, Result<T,E> over exceptions, immutable state via spread/map/filter, and pure functions composed in pipelines.

When to use

Verbatim trigger phrases:

• "make this functional"
• "remove the class"
• "use Result instead of throw"
• "stop mutating this"
• "refactor to factory function"
• "compose these as pure functions"
• "use immutable state"

When NOT to use