Fix TS import generation (#1226)

* Fix TS import generation

* Flatten

packages/util-crypto/src/base32/helpers.ts

@@ -1,10 +1,20 @@
 // Copyright 2017-2021 @polkadot/util-crypto authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import type { U8aLike } from '@polkadot/util/types';
-
 import { assert, u8aToU8a } from '@polkadot/util';
 
+// NOTE: Work around a TS issue. These are re-defined like in @polkadot/util/types
+// since without it the import
+//
+//   import type { U8aLike } from '@polkadot/util/types';
+//
+// ends up in the build-generated code as
+//
+//   import("../../../util/src/types").U8aLike
+//
+// eslint-disable-next-line @typescript-eslint/ban-types
+type U8aLike = number[] | Buffer | Uint8Array | string | String;
+
 interface Coder {
   decode: (value: string) => Uint8Array;
   encode: (value: Uint8Array) => string;