A simple utility for promisifying functions and classes.


1012.0.4a month ago3 years agoMinified + gzip package size for @google-cloud/promisify in KB


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Google Cloud Common Promisify: Node.js Client

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A simple utility for promisifying functions and classes.

A comprehensive list of changes in each version may be found in the CHANGELOG.

Read more about the client libraries for Cloud APIs, including the older Google APIs Client Libraries, in Client Libraries Explained.

Table of contents:


Installing the client library

npm install @google-cloud/promisify

Using the client library

const {promisify} = require('@google-cloud/promisify');

 * This is a very basic example function that accepts a callback.
function someCallbackFunction(name, callback) {
  if (!name) {
    callback(new Error('Name is required!'));
  } else {
    callback(null, `Well hello there, ${name}!`);

// let's promisify it!
const somePromiseFunction = promisify(someCallbackFunction);

async function quickstart() {
  // now we can just `await` the function to use it like a promisified method
  const [result] = await somePromiseFunction('nodestronaut');

It's unlikely you will need to install this package directly, as it will be installed as a dependency when you install other @google-cloud packages.


Samples are in the samples/ directory. Each sample's README.md has instructions for running its sample.

Sample Source Code Try it
Quickstart source code Open in Cloud Shell

The Google Cloud Common Promisify Node.js Client API Reference documentation also contains samples.

Supported Node.js Versions

Our client libraries follow the Node.js release schedule. Libraries are compatible with all current active and maintenance versions of Node.js.

Client libraries targeting some end-of-life versions of Node.js are available, and can be installed via npm dist-tags. The dist-tags follow the naming convention legacy-(version).

Legacy Node.js versions are supported as a best effort:

  • Legacy versions will not be tested in continuous integration.
  • Some security patches may not be able to be backported.
  • Dependencies will not be kept up-to-date, and features will not be backported.

Legacy tags available

  • legacy-8: install client libraries from this dist-tag for versions compatible with Node.js 8.


This library follows Semantic Versioning.

This library is considered to be General Availability (GA). This means it is stable; the code surface will not change in backwards-incompatible ways unless absolutely necessary (e.g. because of critical security issues) or with an extensive deprecation period. Issues and requests against GA libraries are addressed with the highest priority.

More Information: Google Cloud Platform Launch Stages


Contributions welcome! See the Contributing Guide.

Please note that this README.md, the samples/README.md, and a variety of configuration files in this repository (including .nycrc and tsconfig.json) are generated from a central template. To edit one of these files, make an edit to its templates in directory.


Apache Version 2.0


If you find any bugs or have a feature request, please open an issue on github!

The npm package download data comes from npm's download counts api and package details come from npms.io.