# whenplus > A lightweight Promise and when() implementation, plus other async goodies. Latest version **1.7.1g** (published 2013-04-17) · 0 weekly downloads ## Install ```sh npm install whenplus pnpm add whenplus yarn add whenplus bun add whenplus ``` ## Health **Score 15/100 (F)** — status: abandoned. Positive: no vulnerabilities. Warnings: low downloads; no types; no esm support. Negative: abandoned; low maintenance score. ## Facts | | | |---|---| | Version | 1.7.1g | | Published | 2013-04-17 | | First published | 2013-04-17 | | Weekly downloads | 0 | | TypeScript types | none | | Module format | CommonJS | | Dependencies | 0 | | Known vulnerabilities | 0 | | Install scripts | no | | Maintainers | icodeforlove | | Keywords | promise, promises, deferred, deferreds, when, async, asynchronous, cujo | ## Links - npm: https://www.npmjs.com/package/whenplus - Issues: https://github.com/cujojs/when/issues - npm.io page: https://npm.io/package/whenplus ## Alternatives - [@commercetools/sync-actions](https://npm.io/package/@commercetools/sync-actions.md) — 25.1K weekly downloads - [cwait](https://npm.io/package/cwait.md) — 21.4K weekly downloads - [@ledgerhq/hw-app-cosmos](https://npm.io/package/@ledgerhq/hw-app-cosmos.md) — 4.2K weekly downloads - [@financial-times/o-loading](https://npm.io/package/@financial-times/o-loading.md) — 2.8K weekly downloads - [fa](https://npm.io/package/fa.md) — 185 weekly downloads ## Recent versions - 1.7.1g (latest) — 2013-04-17 ## README # when.js [![Build Status](https://secure.travis-ci.org/cujojs/when.png)](http://travis-ci.org/cujojs/when) When.js is cujojs's lightweight [CommonJS](http://wiki.commonjs.org/wiki/Promises) [Promises/A](http://wiki.commonjs.org/wiki/Promises/A) and `when()` implementation, derived from the async core of [wire.js](https://github.com/cujojs/wire), cujojs's IOC Container. It also provides several other useful Promise-related concepts, such as joining multiple promises, mapping and reducing collections of promises, timed promises, and has a robust [unit test suite](#running-the-unit-tests). It passes the [Promises/A Test Suite](https://github.com/domenic/promise-tests), is [frighteningly fast](https://github.com/cujojs/promise-perf-tests#test-results), and is **under 1.3k** when compiled with Google Closure (w/advanced optimizations) and gzipped, and has no dependencies. # What's New? ### 1.7.1 * Removed leftover internal usages of `deferred.then`. * [when/debug](https://github.com/cujojs/when/wiki/when-debug) allows configuring the set of "fatal" error types that will be rethrown to the host env. ### 1.7.0 * **DEPRECATED:** `deferred.then` [is deprecated](when/blob/master/docs/api.md#deferred) and will be removed in an upcoming release. Use `deferred.promise.then` instead. * [promise.yield](when/blob/master/docs/api.md#yield)(promiseOrValue) convenience API for substituting a new value into a promise chain. * [promise.spread](when/blob/master/docs/api.md#spread)(variadicFunction) convenience API for spreading an array onto a fulfill handler that accepts variadic arguments. [Mmmm, buttery](http://s.shld.net/is/image/Sears/033W048977110001_20100422100331516?hei=1600&wid=1600&op_sharpen=1&resMode=sharp&op_usm=0.9,0.5,0,0) * Doc improvements: * [when()](when/blob/master/docs/api.md#when) and [promise.then()](when/blob/master/docs/api.md#main-promise-api) have more info about callbacks and chaining behavior. * More info and clarifications about the roles of [Deferred](when/blob/master/docs/api.md#deferred) and [Resolver](when/blob/master/docs/api.md#resolver) * Several minor clarifications for various APIs * Internal improvements to assimilation and interoperability with other promise implementations. ### 1.6.1 * Fix for accidental coercion of non-promises. See [#62](https://github.com/cujojs/when/issues/60). ### 1.6.0 * New [when.join](when/blob/master/docs/api.md#whenjoin) - Joins 2 or more promises together into a single promise. * [when.some](when/blob/master/docs/api.md#whensome) and [when.any](when/blob/master/docs/api.md#whenany) now act like competitive races, and have generally more useful behavior. [Read the discussion in #60](https://github.com/cujojs/when/issues/60). * *Experimental* progress event propagation. Progress events will propagate through promise chains. [Read the details here](when/blob/master/docs/api.md#progress-events). * *Temporarily* removed calls to `Object.freeze`. Promises are no longer frozen due to a horrendous v8 performance penalty. [Read discussion here](https://groups.google.com/d/topic/cujojs/w_olYqorbsY/discussion). * **IMPORTANT:** Continue to treat promises as if they are frozen, since `freeze()` will be reintroduced once v8 performance improves. * [when/debug](https://github.com/cujojs/when/wiki/when-debug) now allows setting global a debugging callback for rejected promises. [Full Changelog](https://github.com/cujojs/when/wiki/Changelog) # Docs & Examples [API docs](when/blob/master/docs/api.md#api) [More info on the wiki](https://github.com/cujojs/when/wiki) [Examples](https://github.com/cujojs/when/wiki/Examples) Quick Start =========== ### AMD 1. `git clone https://github.com/cujojs/when` or `git submodule add https://github.com/cujojs/when` 1. Configure your loader with a package: ```javascript packages: [ { name: 'when', location: 'path/to/when/', main: 'when' }, // ... other packages ... ] ``` 1. `define(['when', ...], function(when, ...) { ... });` or `require(['when', ...], function(when, ...) { ... });` ### Script Tag 1. `git clone https://github.com/cujojs/when` or `git submodule add https://github.com/cujojs/when` 1. `` 1. `when` will be available as `window.when` ### Node 1. `npm install when` 1. `var when = require('when');` ### RingoJS 1. `ringo-admin install cujojs/when` 1. `var when = require('when');` # Running the Unit Tests ## Node Note that when.js includes @domenic's [Promises/A Test Suite](https://github.com/domenic/promise-tests). Running unit tests in Node will run both when.js's own test suite, and the Promises/A Test Suite. 1. `npm install` 1. `npm test` ## Browsers 1. `npm install` 1. `npm start` - starts buster server & prints a url 1. Point browsers at /capture, e.g. `localhost:1111/capture` 1. `npm run-script test-browser` References ---------- Much of this code was inspired by @[unscriptable](https://github.com/unscriptable)'s [tiny promises](https://github.com/unscriptable/promises), the async innards of [wire.js](https://github.com/cujojs/wire), and some gists [here](https://gist.github.com/870729), [here](https://gist.github.com/892345), [here](https://gist.github.com/894356), and [here](https://gist.github.com/894360) Some of the code has been influenced by the great work in [Q](https://github.com/kriskowal/q), [Dojo's Deferred](https://github.com/dojo/dojo), and [uber.js](https://github.com/phiggins42/uber.js). --- _Source: https://npm.io/package/whenplus · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._