@polkadot/util-crypto/address/encode.js

// Copyright 2017-2022 @polkadot/util-crypto authors & contributors
// SPDX-License-Identifier: Apache-2.0
// Original implementation: https://github.com/paritytech/polka-ui/blob/4858c094684769080f5811f32b081dd7780b0880/src/polkadot.js#L34
import { u8aConcat } from '@polkadot/util';
import { base58Encode } from "../base58/index.js";
import { decodeAddress } from "./decode.js";
import { defaults } from "./defaults.js";
import { sshash } from "./sshash.js";
export function encodeAddress(key, ss58Format = defaults.prefix) {
  // decode it, this means we can re-encode an address
  const u8a = decodeAddress(key);

  if (ss58Format < 0 || ss58Format > 16383 || [46, 47].includes(ss58Format)) {
    throw new Error('Out of range ss58Format specified');
  } else if (!defaults.allowedDecodedLengths.includes(u8a.length)) {
    throw new Error(`Expected a valid key to convert, with length ${defaults.allowedDecodedLengths.join(', ')}`);
  }

  const input = u8aConcat(ss58Format < 64 ? [ss58Format] : [(ss58Format & 0b0000000011111100) >> 2 | 0b01000000, ss58Format >> 8 | (ss58Format & 0b0000000000000011) << 6], u8a);
  return base58Encode(u8aConcat(input, sshash(input).subarray(0, [32, 33].includes(u8a.length) ? 2 : 1)));
}