documentcloud/underscore — pull request #391 by jdalton (2011-12-04 03:10:14+00:00)
Title: Allow _.reduce and _.reduceRight to have an explicitly undefined initial value

Allow _.reduce and _.reduceRight to have an explicitly undefined initial value as the native fork allows.
Fixes the previous issues w/ the patch that caused it to be [reverted](https://github.com/documentcloud/underscore/commit/19beb29283cf5cdcf1c4f4ff2140378a01d31ceb).