import type { AnyString } from '../types.js';
/**
 * @name stringToU8a
 * @summary Creates a Uint8Array object from a utf-8 string.
 * @description
 * String input values return the actual encoded `UInt8Array`. `null` or `undefined` values returns an empty encoded array.
 * @example
 * <BR>
 *
 * ```javascript
 * import { stringToU8a } from '@polkadot/util';
 *
 * stringToU8a('hello'); // [0x68, 0x65, 0x6c, 0x6c, 0x6f]
 * ```
 */
export declare function stringToU8a(value?: AnyString | null): Uint8Array;