Read a file synchronously and parse it to base64 using the builtin Buffer class

sync_base64.js

var fs = require('fs');

const gMinLength = 3;

const gFile = '/tmp/test';
const gEncoding = 'ascii';

function sample1() {
  var data = fs.readFileSync(gFile);
  var buff = Buffer.from(data, gEncoding);
  return buff.toString('base64');
}

function sample2() {
  var buff = new Buffer(0);
  var buffSize = gMinLength * 24;

  var fd = fs.openSync(gFile, 'r');

  var length = 0;
  var buffer = new Buffer(buffSize);

  // could be better?
  while (true) {
    var num = fs.readSync(fd, buffer, 0, buffSize, length);

    if (!num) {
      break;
    }

    var newBuffLength = buff.length + num;
    buff = Buffer.concat([buff, buffer], newBuffLength);

    length += num;
  }

  return buff.toString('base64');
}

console.log(sample1());
console.log(sample2());