Type alias UniqueArray<T, Seen>

UniqueArray<T, Seen>: T extends readonly [infer Head, ...(infer Tail)]
    ? Head extends Seen
        ? ["Encountered duplicate element", Head]
        : readonly [Head, ...UniqueArray<Tail, Seen | Head>]
    : T

Represents a unique array type that filters out duplicate elements. If a duplicate is encountered, it returns a tuple with an error message and the duplicate element.

Type Parameters

  • T extends readonly any[]

    The type of the elements in the array, which must be a readonly array.

  • Seen = never

Returns

A readonly array of unique elements or a tuple indicating a duplicate.

Example

type Result1 = UniqueArray<[1, 2, 3, 1]>; // Result: ['Encountered duplicate element', 1]
type Result2 = UniqueArray<[1, 2, 3]>; // Result: [1, 2, 3]
type Result3 = UniqueArray<[]>; // Result: []

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