Example promisify util from Node.js to convert a callback to a promise

promisify.js

const { promisify } = require("util");

// Example legacy callback function with schema callback(err, response)
const legacyFunctionAPI = (name, callback) => {
  setTimeout(() => {
    if (Math.random() < 0.5) {
      callback(null, { id: 2, name });
    } else {
      callback(new Error("The API has fail"), null);
    }
  }, 1000);
};

// Convert the legacy callback to a Promise
const promiseLegacyFunctionAPI = promisify(legacyFunctionAPI);

// Example using the legacy
legacyFunctionAPI("victoria", (err, response) => {
  if (err) {
    console.log("Error with legacy callback", err);
  } else {
    console.log("Response with legacy callback", response);
  }
});

// Example using the promisify helper
(async () => {
  try {
    const response = await promiseLegacyFunctionAPI("victoria");
    console.log("Response with promise", response);
  } catch (err) {
    console.log("Error with promise", err);
  }
})();