Merge pull request jashkenas#1917 from tjbarber/avoid-returning-zero-…

…truthy-isSorted Fixes jashkenas#1870: _.indexOf with `isSorted` of `true` will incorrectly match `undefined` on an empty array.
yurisklar · Nov 4, 2014 · 3397cad · 3397cad
2 parents 2115d56 + 43dbb7d
commit 3397cad
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diff --git a/test/arrays.js b/test/arrays.js
@@ -306,6 +306,9 @@
       strictEqual(_.indexOf(array, 1, fromIndex), 0);
     });
     strictEqual(_.indexOf([1, 2, 3], 1, true), 0);
+
+    index = _.indexOf([], undefined, true);
+    equal(index, -1, 'empty array with truthy `isSorted` returns -1');
   });
 
   test('lastIndexOf', function() {

diff --git a/underscore.js b/underscore.js
@@ -600,7 +600,7 @@
     var i = 0, length = array && array.length;
     if (typeof isSorted == 'number') {
       i = isSorted < 0 ? Math.max(0, length + isSorted) : isSorted;
-    } else if (isSorted) {
+    } else if (isSorted && length) {
       i = _.sortedIndex(array, item);
       return array[i] === item ? i : -1;
     }