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Underscore.js is a JavaScript utility-library created by Jeremy Ashkenas that provides a broad set of functions for working with arrays, objects, functions, and other data types — essentially a “utility belt” for functional programming in JS. Instead of extending built-in objects or modifying prototypes, Underscore provides its helpers in a single _ namespace, enabling cross-browser support and consistent behaviour across environments. It offers map/filter/reduce, deep-cloning, templating, object traversal, function binding, and more, which makes it easier to write concise, expressive code rather than verbose loops and conditional logic. Many other libraries and frameworks (including Backbone) historically depended on or partnered with Underscore for their utility functions. Even though ES6+ and Lodash have overshadowed some of its role, Underscore remains influential and educational for how to design utility APIs.
Features
- Map, filter, reduce and other functional helpers for arrays and objects
- Utility functions for function binding, partial application and context-control
- Deep-clone, extend, mixin for object-composition and prototype-safe operations
- Templating support for simple HTML generation inside JS
- Chaining interface to link multiple operations in sequence
- Minimal footprint and safe integration (avoids polluting built-in prototypes)
Project Samples
