Underscore Grease

"Fun Underscore.js plugin that provides a cleaner way to do chaining … if chaining how you roll" - Jeremy Ashkenas, creator of Underscore.

Making Underscore Chaining Slicker

In jQuery, chaining is nice and simple:

$(someElement).css('color', 'red').show();

But while jQuery methods only rarely have return values, all Underscore methods do, which means that Underscore can't chain methods unless you tell it when to start/stop chaining. Because of this, Underscore's chaining syntax isn't as simple as jQuery's:

 _(foo).chain().without({foo:bar}).compact().value();

This mix-in solves that problem by providing an alternative chaining syntax:

_(foo).without_({foo:bar}).compact();

In other words, this mix-in adds new versions of every method in Underscore (except chain; that would be pointless), and each of those new versions has a "_" at the end of the original method name. When these "greased" versions of Underscore methods are called, they return an Underscore-wrapped version of whatever result their non-greased version would have returned.

This allows you to chain as many methods as you want, without ever having to invoke either chain or value:

_(foo).without_({foo:bar}).compact_().flatten_().items();

To use Underscore Grease simply download and add underscore.grease.js to your environment (or, for a production environment, use underscore.grease.min.js instead). It's that simple.

Underscore Grease was created by Jeremy Walker with feedback from GitHub user Nami-Doc. It is licensed under the MIT License.

For the historical origins of Underscore Grease see this GitHub issue thread