base64 in Nodejs and Java

From : https://www.hacksparrow.com/nodejs/base64-encoding-decoding-in-node-js.html
let secretBase64 = Buffer.from(“JavaScript”).toString('base64');
// SmF2YVNjcmlwdA==

var b = new Buffer('JavaScript'); // Buffer 

var s = b.toString('base64');
// SmF2YVNjcmlwdA==
var b = new Buffer('SmF2YVNjcmlwdA==', 'base64')
var s = b.toString();
// JavaScript// -------------------

var b = new Buffer('SmF2YVNjcmlwdA==', 'base64')
var s = b.toString('hex');
// 4a617661536372697074
var b = new Buffer('4a617661536372697074', 'hex')
var s = b.toString('utf8');
// JavaScript//----------------------

$node
>require('crypto').randomBytes(64).toString('hex')
f3a302c14cd2f57bc6972a0d599857dbde877fbf03b38dd592b9635bc7f30299c9d5dfe44e5abb615737cf40a45958c8283b5d1132c4e7e0d8e66610044be1f4
https://expressjs.com/en/api.html

var fs = require('fs');
// function to encode file data to base64 encoded string
function base64_encode(file) {
    // read binary data
    var bitmap = fs.readFileSync(file);
    // convert binary data to base64 encoded string
    return new Buffer(bitmap).toString('base64');
}
// function to create file from base64 encoded string
function base64_decode(base64str, file) {
    // create buffer object from base64 encoded string, it is important to tell the constructor that the string is base64 encoded
    var bitmap = new Buffer(base64str, 'base64');
    // write buffer to file
    fs.writeFileSync(file, bitmap);
    console.log('******** File created from base64 encoded string ********');
}
// convert image to base64 encoded string
var base64str = base64_encode('kitten.jpg');
console.log(base64str);
// convert base64 string back to image 
base64_decode(base64str, 'copy.jpg');
https://www.cnblogs.com/zclub/p/11412255.html

#java.util.Base64
Base64.getEncoder(),Base64.getDecoder()->RFC4648
Base64.getUrlEncoder(),Base64.getUrlDecoder()->RFC4648_URLSAFE
Base64.getMimeEncoder(),Base64.getMimeDecoder()->RFC2045
Reference: https://www.ietf.org/rfc/rfc4648.txt
https://www.ietf.org/rfc/rfc2045.txt