/**
 * Removes the given element from the array if it exists within the array.
 * @private
 * @param arr An array.
 * @param obj An element to remove from the array.
 * @returns The given array without the given element removed if it was found; otherwise the array without modifications.
 */
export declare const removeIfExists: <T>(arr: T[], obj: T) => T[];
/**
 * Adds the given element to the array if it doesn't exist within the array.
 * @private
 * @param arr An array.
 * @param obj An element to add to the array.
 * @returns The given array with the given element added it was not found; otherwise the array without modifications.
 */
export declare const addIfNotExists: <T>(arr: T[], obj: T) => T[];