Underscore.js

Underscore.js
Name	Underscore.js
Author	Jeremy Ashkenas
Developer	DocumentCloud
Initial release	2009
Repository	GitHub
License	MIT License
Platform	Cross-platform

Underscore.js is a lightweight JavaScript library providing functional utilities for Brendan Eich, Douglas Crockford, ECMAScript 5, ECMAScript 6, Node.js, V8 (JavaScript engine), Chromium, and Mozilla Firefox. It supplies modular helpers inspired by Lodash (JavaScript library), Ruby (programming language), Python (programming language), Haskell, and Lisp (programming language) idioms to ease collection manipulation, function binding, and template rendering for projects from jQuery-centric web apps to Backbone.js and AngularJS integrations.

History

Underscore.js originated in the late 2000s as part of work by Jeremy Ashkenas within DocumentCloud and gained visibility alongside projects like Backbone.js and CoffeeScript. Early development intersected with discussions at GitHub, coordination with contributors from Yahoo!, Mozilla Foundation, Opera Software, and dialogues at conferences such as JSConf, NodeConf, and Y Combinator gatherings. The project evolved through pull requests and issue tracking on GitHub while responding to language changes driven by standards bodies including Ecma International and implementations like Google Chrome, Safari (web browser), and Internet Explorer. Its stewardship involved maintainers active in communities around Open-source software, MIT License stewardship, and integrations discussed at Google I/O, WWDC, and Strange Loop.

Features

Underscore.js exposes a functional toolkit echoing patterns from Ruby Gems, Perl (programming language), Smalltalk, and Clojure sequences. Core features include collection iteration, array utilities, object utilities, function decorators, and templating reminiscent of patterns used in Handlebars (templating language), Mustache, EJS, and server-side frameworks like Ruby on Rails and Django. Utility functions enable composition strategies akin to Functional programming proponents such as John Hughes, Simon Peyton Jones, and languages in the ML (programming language family). It also offers shallow cloning, partial application, memoization, and throttling useful in environments maintained by teams at Netflix, LinkedIn, Airbnb, and Twitter.

API

The API provides methods for arrays, objects, functions, and utilities with names familiar to users of libraries like Lodash (JavaScript library), Prototype (JavaScript framework), and Dojo Toolkit. Collection helpers handle operations related to sequences encountered in Array.prototype proposals and ECMAScript 2015 features, while function helpers mimic behavior discussed in texts by Douglas Crockford and Kyle Simpson. The templating API uses delimiters with roots in Mustache aesthetics and integrates into front-end stacks involving Backbone.js, React (JavaScript library), and Ember.js. Documentation and examples have been shared across platforms like Stack Overflow, Medium (website), Smashing Magazine, and Dev.to with contributions from maintainers tied to MIT Media Lab alumni and contributors associated with Mozilla Developer Network.

Performance and Compatibility

Performance considerations were debated in community threads hosted on GitHub, Stack Overflow, and mailing lists coordinated by W3C participants and engine developers from Google], [Apple, and Microsoft. Benchmarks compared Underscore.js against Lodash (JavaScript library), native Array.prototype.map, Array.prototype.reduce, and implementations in engines such as V8 (JavaScript engine), SpiderMonkey, and Chakra (JavaScript engine). Compatibility targeted browsers including Internet Explorer 6, Internet Explorer 8, Microsoft Edge, Firefox, Chrome, and Safari (web browser) while also supporting Node.js server environments and embed contexts like Adobe Acrobat scripting and Apache Cordova mobile apps.

Adoption and Usage

Underscore.js saw adoption in projects spanning startups accelerated by Y Combinator and enterprises such as LinkedIn, Mozilla, Airbnb, and Twitter where it appeared in dependency graphs on npm (software), Bower (package manager), and CDNJS. It integrated into MVC and MV* frameworks like Backbone.js, Marionette.js, AngularJS, and served as a utility layer for UI libraries such as jQuery UI and Bootstrap (front-end framework). Educational resources by authors like Addy Osmani, Kyle Simpson, Douglas Crockford, and institutions such as MIT, Stanford University, and Harvard University referenced it in tutorials and coursework.

Alternatives and Ecosystem

Alternatives include Lodash (JavaScript library), Ramda (programming library), RxJS, Immutable.js, Sugar (JavaScript library), and native APIs standardized by Ecma International in ECMAScript 2015 and later editions. The ecosystem comprises integrations with build tools and package managers such as Webpack, Browserify, Rollup (software), npm (software), and Yarn (package manager), as well as type annotations via TypeScript and static analysis tools like ESLint and Flow (software). Community forks and extensions appeared in repositories hosted on GitHub, discussed at conferences including JSConf, NodeConf, DotJS, and documented on platforms like MDN Web Docs and GitBook.

Category:JavaScript libraries