es-toolkit/dist/fp/array/uniqBy.d.mts

A state-of-the-art, high-performance JavaScript utility library with a small bundle size and strong type annotations.

//#region src/fp/array/uniqBy.d.ts
/**
 * Creates a function that removes duplicate values by mapped identity.
 *
 * The first value for each mapped key is preserved. The returned function is
 * lazy-capable inside {@link pipe}.
 *
 * @template T - The type of elements in the array.
 * @template U - The type of comparison keys returned by the mapper.
 * @param mapper - Called with each value and index to produce a comparison key.
 * @returns A function that maps the piped array to unique values.
 *
 * @example
 * import { pipe, uniqBy } from 'es-toolkit/fp';
 *
 * pipe([{ id: 1 }, { id: 1 }, { id: 2 }], uniqBy(item => item.id));
 * // => [{ id: 1 }, { id: 2 }]
 */
declare function uniqBy<T, U>(mapper: (item: T, index: number) => U): (array: readonly T[]) => T[];
//#endregion
export { uniqBy };