@bulatlib/res — Rust‑style Result for TypeScript

Small, strict utilities for Rust‑style (Ok/Err) results. Provides safe constructors, execution wrappers, and transformation chains via pipe.

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``bash
npm i @bulatlib/res


or

pnpm add @bulatlib/res

or

bun add @bulatlib/res
`

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- Core types
- Res: union { ok: T; err?: never } | { ok?: never; err: Error }.

- Constructors
- ok(value) — create a successful result.
- err(error) — create an error result.

- Safe execution
- wrap(fn) — run a sync function with try/catch and return Res.
- wrapAsync(fn) — run an async function with try/catch and return Promise>.

- Pipe
- pipe.from(res) — wraps Res and returns Pipe with chainable methods.
- Pipe methods:
- map(fn) — Ok(T) -> Ok(fn(T)), Err unchanged.
- mapErr(fn) — transform Error to Err(fn(err)).
- mapOr(default, fn) — on Ok return Ok(fn(T)), on Err return Ok(default).
- mapOrElse(defaultFn, fn) — on Ok return Ok(fn(T)), on Err return Ok(defaultFn(err)).
- and(res) — if Ok, return the second res, otherwise keep original Err.
- andThen(fn) — if Ok, evaluate fn(T): Res, otherwise Err.
- or(res) — if Ok, return it; otherwise return the second res.
- orElse(fn) — if Err, evaluate fn(err): Res; otherwise keep original Ok.
- unwrapOr(default) — return T or default.
- unwrapOrElse(fn) — return T or fn(err).
- match({ ok, err }) — pattern match and return a value of one of callbacks.
- res() — return raw Res.

- Utilities
- combine(results) — fold Res[] into Res. Returns the first Err if any, otherwise Ok with collected values in order.

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Examples will be added soon. Meanwhile, please check the test files in src (e.g., src/*.test.ts`) for usage examples.

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MIT