diff --git a/test/arrays.js b/test/arrays.js index 2d69235c4..02e282b8a 100644 --- a/test/arrays.js +++ b/test/arrays.js @@ -26,8 +26,12 @@ $(document).ready(function() { test("arrays: last", function() { equals(_.last([1,2,3]), 3, 'can pull out the last element of an array'); + equals(_.last([1,2,3], 0).join(', '), "", 'can pass an index to last'); + equals(_.last([1,2,3], 2).join(', '), '2, 3', 'can pass an index to last'); var result = (function(){ return _(arguments).last(); })(1, 2, 3, 4); equals(result, 4, 'works on an arguments object'); + result = _.map([[1,2,3],[1,2,3]], _.last); + equals(result.join(','), '3,3', 'works well with _.map'); }); test("arrays: compact", function() { diff --git a/underscore.js b/underscore.js index fcd3d09c9..7cbb653aa 100644 --- a/underscore.js +++ b/underscore.js @@ -306,9 +306,10 @@ return slice.call(array, (index == null) || guard ? 1 : index); }; - // Get the last element of an array. - _.last = function(array) { - return array[array.length - 1]; + // Get the last element of an array. Passing **n** will return the last N + // values in the array. The **guard** check allows it to work with `_.map`. + _.last = function(array, n, guard) { + return (n != null) && !guard ? slice.call(array, array.length - n) : array[array.length - 1]; }; // Trim out all falsy values from an array.