/**
 * @name compactAddLength
 * @description Adds a length prefix to the input value
 * @example
 * <BR>
 *
 * ```javascript
 * import { compactAddLength } from '@polkadot/util';
 *
 * console.log(compactAddLength(new Uint8Array([0xde, 0xad, 0xbe, 0xef]))); // Uint8Array([4 << 2, 0xde, 0xad, 0xbe, 0xef])
 * ```
 */
export declare function compactAddLength(input: Uint8Array): Uint8Array;