type Narrowable = string | number | boolean | object | null | undefined | symbol;
type Invalid<T> = Error & {
    __errorMessage: T;
};
type AsUniqueArray<A extends readonly any[], B extends readonly any[]> = {
    [I in keyof A]: unknown extends {
        [J in keyof B]: J extends I ? never : B[J] extends A[I] ? unknown : never;
    }[number] ? Invalid<[A[I], 'is repeated']> : A[I];
};
/**
 * This is a function to identify duplicates in arrays during compile time.
 * You may find it useful if you have a list of constants and you need them to be unique.
 * @see https://stackoverflow.com/a/57021889
 */
export declare const asUniqueArray: <N extends Narrowable, A extends [] | (readonly N[] & AsUniqueArray<A, A>)>(a: A) => A;
export {};