Convert image to base64 using Node.js' native libs

converter.js

// Usage: node converter.js <file path>

const {
  promises: { readFile, writeFile },
} = require("fs");

const [, , filePath] = process.argv;

async function converter(path) {
  return readFile(path)
    .then((buffer) =>
      writeFile(
        "base64.txt",
        buffer.toString("base64")
      )
    );
}

converter(filePath).then(() => {
  process.stdout.write(`\nOutput:\n${__dirname}\\base64.txt\n`);
});