zena:encoding

Binary-to-text encodings, and a check for UTF-8.

BaseEncoding implements the encodings of RFC 4648: an alphabet of 16, 32 or 64 characters, each standing for 4, 5 or 6 bits of the input. The common ones are ready to use:

• hex: base16 in lowercase. Decoding accepts either case.
• base32: the RFC 4648 alphabet, A-Z and 2-7.
• base32Lower: the same alphabet in lowercase, as multibase and CIDs use.
• base64: A-Z, a-z, 0-9, + and /.
• base64Url: the URL- and filename-safe alphabet, with - and _ for + and /, as JWTs use.

import {base64, base64Url, hex} from 'zena:encoding';

let text = base64.encode(bytes);                 // padded with '='
let token = base64Url.encode(bytes, false);      // unpadded
let digest = hex.decode('e3b0c442');

encode pads with = unless pad is false. decode accepts text with or without padding. It throws EncodingError for a character outside the alphabet, for a length that no byte string encodes to, for padding of the wrong length, and for a last character with bits set beyond the last whole byte. So a byte string has exactly one unpadded encoding and one padded one, and decoding never accepts two different texts as the same bytes in the same form.