Encode file to base64 and outputs in console.

base64_encode.js

const fs = require('fs');

const f = process.argv[2];

fs.access(f, fs.R_OK, (err) => {
  if (err) {
    kill(`Cannot acces ${f}`);
  }

  readFile();
});

readFile = () => {
    fs.readFile(f, (err, data) => {
      if (err) {
        kill('Cannot read file', err);
      }

      console.log(data.toString('base64'));
    });
}

kill = (message, err) => {
    console.log(message, err || '');
    process.exit(1);
}