session-desktop/ts/session/crypto/index.ts

import * as MessageEncrypter from './MessageEncrypter';

export { MessageEncrypter };

// libsodium-wrappers requires the `require` call to work
// tslint:disable-next-line: no-require-imports
import libsodiumwrappers = require('libsodium-wrappers');

export async function getSodium(): Promise<typeof libsodiumwrappers> {
  await libsodiumwrappers.ready;
  return libsodiumwrappers;
}

export const concatUInt8Array = (...args: Array<Uint8Array>): Uint8Array => {
  const totalLength = args.reduce((acc, current) => acc + current.length, 0);

  const concatted = new Uint8Array(totalLength);
  let currentIndex = 0;
  args.forEach(arr => {
    concatted.set(arr, currentIndex);
    currentIndex += arr.length;
  });

  return concatted;
};