unique.ts

/**
 * @fileoverview Deduplicate an array via `Set`. Preserves
 * first-occurrence order.
 */

import { SetCtor } from '../primordials/map-set'

/**
 * Get unique values from an array.
 *
 * Returns a new array containing only the unique values from the input array.
 * Uses `Set` internally for efficient deduplication. Order of first occurrence
 * is preserved.
 *
 * @param arr - The array to deduplicate (can be readonly)
 * @returns New array with duplicate values removed
 *
 * @example
 * ```ts
 * // Remove duplicate numbers
 * arrayUnique([1, 2, 2, 3, 1, 4])
 * // Returns: [1, 2, 3, 4]
 *
 * // Remove duplicate strings
 * arrayUnique(['apple', 'banana', 'apple', 'cherry'])
 * // Returns: ['apple', 'banana', 'cherry']
 *
 * // Works with readonly arrays
 * const readonlyArr = [1, 1, 2] as const
 * arrayUnique(readonlyArr)
 * // Returns: [1, 2]
 *
 * // Empty arrays return empty
 * arrayUnique([])
 * // Returns: []
 * ```
 */
/*@__NO_SIDE_EFFECTS__*/
export function arrayUnique<T>(arr: T[] | readonly T[]): T[] {
  return [...new SetCtor(arr)]
}