Comments on: Extending Objects in Underscore

By: Mike DiLorenzo

Mike DiLorenzo — Thu, 11 Apr 2013 16:53:00 +0000

jQuery’s extend does a deep copy of nested objects. Underscore’s shallow copy of nested attributes can lead to some very subtle bugs. Take a look at the following article for a good discussion of the issue:

http://techiella.wordpress.com/2013/04/02/underscore-js-extend-vs-jquery-extend/

By: jmav

jmav — Sun, 14 Oct 2012 16:32:00 +0000

jQuery $.extend offer same functionality?

By: The Morning Brew - Chris Alcock » The Morning Brew #1205

The Morning Brew - Chris Alcock » The Morning Brew #1205 — Mon, 08 Oct 2012 08:33:13 +0000

[...] Extending Objects in Underscore – Chris Missal continues his object extension in JavaScript series with a look at how you can extend objects using the Underscore library, which provides the basis of Backbone JS [...]

By: Chris Tavares

Chris Tavares — Sat, 06 Oct 2012 03:30:00 +0000

You’re missing an important semantic here – _.extend modifies the first object you pass it. So after you call _.extend(start, more, extra), the start object has changed. In fact, start is the object that is returned. Your example makes it look like start isn’t modified.

By: Mike Murray

Mike Murray — Fri, 05 Oct 2012 19:00:00 +0000

You can also use the alternate Underscore syntax:

var extended = _(start).extend(more, extra);