@thi.ng/base-n/chars/26.js

Arbitrary base-n conversions w/ presets for base8/16/32/36/58/62/64/83/85, support for bigints and encoding/decoding of byte arrays

const B26_UC_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const B26_LC_CHARS = "abcdefghijklmnopqrstuvwxyz";
const B26_CHARS = B26_LC_CHARS;
export {
  B26_CHARS,
  B26_LC_CHARS,
  B26_UC_CHARS
};