import { compactAddLength } from "https://deno.land/x/polkadot@0.2.17/util/compact/addLength.ts";
Examples
import { compactAddLength } from 'https://deno.land/x/polkadot@0.2.17/util/mod.ts';
console.log(compactAddLength(new Uint8Array([0xde, 0xad, 0xbe, 0xef]))); // Uint8Array([4 << 2, 0xde, 0xad, 0xbe, 0xef])