编码和解码 base64 数据

const bytes = new Uint8Array([98, 117, 110]);
const encoded = bytes.toBase64(); // => "YnVu"

const decoded = Uint8Array.fromBase64(encoded);
// => Uint8Array(3) [ 98, 117, 110 ]

const bytes = new TextEncoder().encode("hello world");
const encoded = bytes.toBase64(); // => "aGVsbG8gd29ybGQ="

const decoded = Uint8Array.fromBase64(encoded);
const text = new TextDecoder().decode(decoded); // => "hello world"

const encoded = Buffer.from("hello world").toBase64();
// => "aGVsbG8gd29ybGQ="

const bytes = Buffer.from(encoded, "base64");
bytes instanceof Uint8Array; // => true

const text = bytes.toString("utf8");
// => "hello world"