lie

What is lie?

The 'lie' npm package is a lightweight, performant promise library implementing the Promises/A+ specification. It provides a simple way to work with asynchronous operations in JavaScript, allowing developers to create, manage, and compose promises for better asynchronous flow control.

What are lie's main functionalities?

Creating a new promise

This feature allows you to create a new promise. The constructor takes a function that contains the asynchronous operation. The function provides two arguments, resolve and reject, which are used to settle the promise.

var Promise = require('lie');
var myPromise = new Promise(function (resolve, reject) {
  // Asynchronous operation here
  if (/* operation successful */) {
    resolve('Success!');
  } else {
    reject('Failure!');
  }
});

Promise resolution

This feature is used to create a promise that is immediately resolved with a given value. It's useful for converting values to promises.

var Promise = require('lie');
Promise.resolve('Immediate resolve').then(function (value) {
  console.log(value); // 'Immediate resolve'
});

Promise rejection

This feature is used to create a promise that is immediately rejected with a given reason. It's useful for representing asynchronous operations that have failed.

var Promise = require('lie');
Promise.reject(new Error('Immediate reject')).catch(function (error) {
  console.error(error); // Error: 'Immediate reject'
});

Chaining promises

This feature allows you to chain multiple promises together and perform actions once all of them are settled. The Promise.all method returns a single promise that resolves when all of the promises in the iterable argument have resolved.

var Promise = require('lie');
var p1 = Promise.resolve(3);
var p2 = 1337;
var p3 = new Promise(function (resolve, reject) {
  setTimeout(resolve, 100, 'foo');
});

Promise.all([p1, p2, p3]).then(function (values) {
  console.log(values); // [3, 1337, 'foo']
});

Other packages similar to lie

bluebird

Bluebird is a full-featured promise library with a focus on innovative features and performance. It is often considered one of the fastest promise libraries and includes additional utilities for concurrency, filtering, mapping, and more. Compared to 'lie', Bluebird is more feature-rich but also larger in size.

q

Q is one of the earliest promise libraries that implements the Promises/A+ specification. It provides a robust set of features for creating and managing promises. While 'lie' focuses on minimalism and performance, Q offers a wider API surface and additional features like progress notifications for long-running asynchronous operations.

es6-promise

The es6-promise library is a polyfill for the ES6 Promise specification. It aims to provide a lightweight and efficient implementation of promises for environments that do not natively support them. Compared to 'lie', es6-promise is more about compatibility with the ES6 standard, while 'lie' is a standalone implementation with a focus on being lightweight.

README

lie

lie is a JavaScript promise/deferred implementation, implementing the Promises/A+ spec, with the goal of implementing the spec as closely as possible and nothing else, this means created promises only have a then method and promises may only be created by passing a resolver function to the constructor. Lie is not meant to compete with Q, When, or any of the other promise libraries that already exist, it is meant to be a library you could use to create a Q or When style tool belt, which I did over here.

A fork of Ruben Verborgh's library called promiscuous. Which takes advantage of my immediate library, uses object constructors, and with a name I can actually consistently spell. Plus if I learned anything from catiline (formally communist) it's that you don't want to pick an even mildly offensive name.

API

by defailt adds a function called 'promise' to the global scope (or if you grab the noConflict version than one called lie)

return a promise

function waitAwhile(){
	return promise(function(resolve,reject){
	    doSomething(functin(err,result){
	        if(err){
	            reject(err);
	        }else{
	            resolve(result);
	        }
	    });
	});
}

Write a function turns node style callback to promises

function denodify(func){
    return function() {
        var args = Array.prototype.concat.apply([], arguments);
        return promise(function(resolve, reject) {
            args.push(function(err, success) {
                if (err) {
                    reject(err);
                }
                else {
                    resolve(success);
                }
            });
            func.apply(undefined, args);
        });
    };
};

##node

install with npm install lie, exactly the same as above but

var promise = require('lie');