import type { Arr } from '@toolbox-ts/types/defs/array';
/**
 * Inserts an element or elements into an array at the specified index.
 *
 * @param t - The target array to insert elements into.
 * @param e - The element or elements to insert into the array.
 * @param i - The index at which to insert the elements.
 * @returns A new array with the elements inserted at the specified index.
 *
 * @example
 * ```ts
 * const arr = [1, 2, 3];
 * const newArr = insert(arr, 4, 1);
 * console.log(newArr); // [1, 4, 2, 3]
 * ```
 *
 */
export declare function insert<T extends Arr = Arr, E = unknown>(t: T, e: E, i: number): ((E & any[]) | E[])[number][];