aureooms/js-codec-base64

import {toObject, inverse} from '@iterable-iterator/mapping';
import {enumerate} from '@iterable-iterator/zip';

const variants = {
    // Standard
    RFC4648: {
        alphabet:
            'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/',
        padding: '=',
    },

    // Unpadded base64url
    RFC7515: {
        alphabet:
            'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_',
        padding: false,
    },

    // YUI library
    Y64: {
        alphabet:
            'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789._',
        padding: '-',
    },

    // IMAP mailbox names
    RFC3501: {
        alphabet:
            'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,',
        padding: false,
    },
};

for (const variant in variants) {
    if (Object.hasOwn(variants, variant)) {
        variants[variant].index = toObject(
            inverse(enumerate(variants[variant].alphabet)),
        );
    }
}

export default variants;