effect-io-ai

Package: effect
Module: Tuple

Tuple.isTupleOf

Checks whether an array has exactly N elements, narrowing the type to a fixed-length tuple.

When to use

Use to guard that an array has exactly the tuple length expected at runtime.

Details

This is a re-export of Predicate.isTupleOf. It narrows the type to TupleOf<N, T> in the truthy branch.

Gotchas

This only checks .length; it does not validate element types.

Example (Checking exact length)

import { Tuple } from "effect"

const arr: Array<number> = [1, 2, 3]
if (Tuple.isTupleOf(arr, 3)) {
  console.log(arr)
  // ^? [number, number, number]
}

See

• isTupleOfAtLeast – check for a minimum length

Signature

declare const isTupleOf: { <N extends number>(n: N): <T>(self: ReadonlyArray<T>) => self is TupleOf<N, T>; <T, N extends number>(self: ReadonlyArray<T>, n: N): self is TupleOf<N, T>; }

Source

Since v3.3.0