@types/q

What is @types/q?

@types/q provides TypeScript type definitions for the Q library, which is a tool for working with promises in JavaScript. It allows developers to write asynchronous code in a more manageable and readable way.

What are @types/q's main functionalities?

Creating Promises

This feature allows you to create a new promise using Q.defer(). The deferred object has a promise property that can be used to attach handlers for the resolved and rejected states.

const Q = require('q');
const deferred = Q.defer();
deferred.promise.then((value) => {
  console.log('Resolved with:', value);
}).catch((error) => {
  console.error('Rejected with:', error);
});
deferred.resolve('Success');

Chaining Promises

This feature demonstrates how to chain multiple promises together using Q.fcall() and .then(). Each step in the chain can return a value or a new promise, allowing for sequential asynchronous operations.

const Q = require('q');
Q.fcall(() => {
  return 'First step';
}).then((result) => {
  console.log(result);
  return 'Second step';
}).then((result) => {
  console.log(result);
  return 'Third step';
}).then((result) => {
  console.log(result);
}).catch((error) => {
  console.error('Error:', error);
});

Handling Multiple Promises

This feature shows how to handle multiple promises concurrently using Q.all(). It waits for all promises in the array to resolve and then returns an array of results. If any promise is rejected, it will catch the error.

const Q = require('q');
const promise1 = Q.delay(1000).then(() => 'First');
const promise2 = Q.delay(2000).then(() => 'Second');
Q.all([promise1, promise2]).then((results) => {
  console.log('All promises resolved:', results);
}).catch((error) => {
  console.error('One or more promises rejected:', error);
});

Other packages similar to @types/q

bluebird

Bluebird is a fully-featured promise library for JavaScript. It offers a wide range of features including promise creation, chaining, and concurrency control. Compared to Q, Bluebird is known for its performance and additional utility methods.

es6-promise

ES6-Promise is a polyfill for the ES6 Promises specification. It provides a lightweight implementation of promises that is compliant with the ES6 standard. While it lacks some of the advanced features of Q, it is a good choice for environments that need ES6 compatibility.

when

When is a solid promise library that focuses on performance and small size. It provides similar functionality to Q, including promise creation and chaining, but is designed to be more lightweight and faster.

README

Installation

npm install --save @types/q

Summary

This package contains type definitions for Q ( https://github.com/kriskowal/q ).

Details

Files were exported from https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/q

Additional Details

• Last updated: Wed, 13 Mar 2019 17:15:46 GMT
• Dependencies: none
• Global values: Q

Credits

These definitions were written by Barrie Nemetchek https://github.com/bnemetchek, Andrew Gaspar https://github.com/AndrewGaspar, John Reilly https://github.com/johnnyreilly, Michel Boudreau https://github.com/mboudreau, TeamworkGuy2 https://github.com/TeamworkGuy2.