Create randomized string

random-string.ts

const unambiguousCharacters = "0123456789abcdefghjkmnpqrstvwxyz"; // excludes i, l, o, u, and uppercase letters

/** Creates a random string of a specified length and using specified characters. */
export function createRandomString(
  length = 16,
  characterSet = unambiguousCharacters
): string {
  if (length <= 0) {
    throw new RangeError("Length must be a positive integer.");
  }

  if (characterSet.length <= 0) {
    throw new RangeError("Character set must not be empty.");
  }

  // Using a Uint8Array limits us to 256 unique characters (2^8), which is sufficient for most use cases.
  if (characterSet.length > 256) {
    throw new RangeError(
      "Character set must not contain more than 256 characters."
    );
  }

  const randomValues = new Uint8Array(length);
  globalThis.crypto.getRandomValues(randomValues);

  return Array.from(
    randomValues,
    (n) => characterSet[n % characterSet.length]
  ).join("");
}