A lightweight, production-ready, universal library for transforming callback-style functions into Promise-based ones. Works seamlessly across Node.js, Deno, and browsers.
📌 Maintenance Status: This library is in maintenance mode. It is well-written, thoroughly tested, and production-ready. Modern JavaScript provides built-in solutions for most promise-related use cases. However, this library remains a reliable choice with zero dependencies (thus zero vulnerabilities) if you need its specific ID-based promise storage feature. While no new features are being developed, bug reports are monitored and fixes are provided when needed.
If you use this project, I'd love to know! Feel free to reach out or star this repo.
- 🌐 Universal Compatibility: Works in Node.js, Deno, and browsers
- 🔒 Type Safety: Full TypeScript support with type definitions
- 🎯 Zero Dependencies: Lightweight and self-contained
- 🔄 Promise Chaining: Full support for Promise chaining and async/await
- 📦 Multiple Module Formats: UMD and ES Module bundles available
- ✅ Production Ready: Battle-tested and fully covered with tests
npm install call-to-promise
# or
yarn add call-to-promise<!-- UMD Bundle -->
<script src="path/to/dist/umd.min.js"></script>
<!-- ES Module -->
<script type="module">
import * as c2p from 'path/to/dist/module.min.mjs';
</script>import * as c2p from 'path/to/dist/module.min.mjs';const c2p = require('call-to-promise'); // or import for ES modules
function add(a, b, callback) {
callback(a + b);
}
// Convert callback to promise
add(3, 4, c2p.successfn('add-result'));
c2p.when('add-result').then(console.log); // -> 7function calculate(a, b, callback) {
callback(a + b, a * b, a - b);
}
calculate(3, 4, c2p.successfn('calc'));
c2p.when('calc').then(console.log); // -> { '0': 7, '1': 12, '2': -1 }const c2p = require('call-to-promise');
const fs = require('fs');
fs.readFile('/etc/hosts', 'utf8', c2p.successfn('read-file'));
c2p.when('read-file').then(([err, data]) => {
if (err) throw err;
console.log(data);
});c2p
.when(['promise1', 'promise2', 'promise3'])
.then((results) => console.log(results));// Global instance (shared across modules)
const c2p = require('call-to-promise');
// Local instance (isolated)
const localC2p = require('call-to-promise').build();While this library remains reliable, here are modern approaches to handle similar scenarios:
const { promisify } = require('util');
const fs = require('fs');
// Convert callback-based function to promise-based
const readFileAsync = promisify(fs.readFile);
// Use it
async function readConfig() {
try {
const data = await readFileAsync('/etc/hosts', 'utf8');
console.log(data);
} catch (err) {
console.error(err);
}
}function promisifyFunction(fn) {
return (...args) => {
return new Promise((resolve, reject) => {
fn(...args, (err, result) => {
if (err) reject(err);
else resolve(result);
});
});
};
}
// Example usage
const readFilePromise = promisifyFunction(fs.readFile);
readFilePromise('/etc/hosts', 'utf8').then(console.log).catch(console.error);// Modern Web APIs are already promise-based
fetch('https://api.example.com/data')
.then((response) => response.json())
.then((data) => console.log(data))
.catch((error) => console.error(error));
// Modern Node.js APIs often provide promise versions
const { readFile } = require('fs/promises');
readFile('/etc/hosts', 'utf8').then(console.log).catch(console.error);- You need to store and manage promises by ID
- You're working with legacy callback-based code and need a consistent way to handle promise creation and storage
- You want a zero-dependency solution that works across all JavaScript environments
successfn(id: string): Creates a success callback for the given IDfailfn(id: string): Creates a failure callback for the given IDwhen(id: string | string[]): Returns a Promise for the given ID(s)id(id: string): Returns the deferred object for direct manipulationbuild(): Creates a new local instance
isPending(): Checks if the promise is pendingisSucceed(): Checks if the promise is fulfilledisFailed(): Checks if the promise is rejectedresolve(value): Resolves the promisereject(error): Rejects the promise
BSD-3-Clause © dominikj111
This library is licensed under the BSD 3-Clause License.