/**
 * @name arrayFlatten
 * @summary Merge T[][] into T[]
 * @description
 * Returns a new array with all arrays merged into one
 * @example
 * <BR>
 *
 * ```javascript
 * import { arrayFlatten } from '@polkadot/util';
 *
 * arrayFlatten([[1, 2], [3, 4], [5]]); // [1, 2, 3, 4, 5]
 * ```
 */
export declare function arrayFlatten<T>(arrays: readonly T[][]): T[];