import {toBytes, toBase64} from 'https://cdn.jsdelivr.net/npm/fast-base64@0.1.8/+esm'

const bytes = toBytes('SGV5byEgV2VsY29tZSB0byB0aGlzIERhaWx5IERyb3AgRXhhbXBsZSBwYWdlIQ=='); 
const textDecoder = new TextDecoder();
const resultString = textDecoder.decode(bytes);

const base64 = toBase64(bytes);