decrypt.js

const NodeRSA = require("node-rsa");
const fs = require("fs");

(async () => {
  const keyData = fs.readFileSync("private.key", "utf8");
  const test = fs.readFileSync("stickers/christianengineer.txt", "utf8");

  const key = NodeRSA();
  key.importKey(keyData);

  const decrypted = key.decrypt(test, "utf8");

  console.log(decrypted);
})();