Merge pull request #2102 from jridgewell/indexof-nan-start

Fix _.indexOf with NaN and startIndex

Author: megawac

test/arrays.js

@@ -344,6 +344,9 @@
     strictEqual(_.indexOf([1, 2, NaN, NaN], NaN), 2, 'Expected [1, 2, NaN] to contain NaN');
     strictEqual(_.indexOf([1, 2, Infinity], NaN), -1, 'Expected [1, 2, NaN] to contain NaN');
 
+    strictEqual(_.indexOf([1, 2, NaN, NaN], NaN, 1), 2, 'startIndex does not affect result');
+    strictEqual(_.indexOf([1, 2, NaN, NaN], NaN, -2), 2, 'startIndex does not affect result');
+
     (function() {
       strictEqual(_.indexOf(arguments, NaN), 2, 'Expected arguments [1, 2, NaN] to contain NaN');
     }(1, 2, NaN, NaN));
@@ -418,6 +421,9 @@
     strictEqual(_.lastIndexOf([1, 2, NaN, NaN], NaN), 3, 'Expected [1, 2, NaN] to contain NaN');
     strictEqual(_.lastIndexOf([1, 2, Infinity], NaN), -1, 'Expected [1, 2, NaN] to contain NaN');
 
+    strictEqual(_.lastIndexOf([1, 2, NaN, NaN], NaN, 2), 2, 'fromIndex does not affect result');
+    strictEqual(_.lastIndexOf([1, 2, NaN, NaN], NaN, -2), 2, 'fromIndex does not affect result');
+
     (function() {
       strictEqual(_.lastIndexOf(arguments, NaN), 3, 'Expected arguments [1, 2, NaN] to contain NaN');
     }(1, 2, NaN, NaN));

underscore.js

@@ -616,7 +616,8 @@
       return array[i] === item ? i : -1;
     }
     if (item !== item) {
-      return _.findIndex(slice.call(array, i), _.isNaN);
+      var index = _.findIndex(slice.call(array, i), _.isNaN);
+      return index >= 0 ? index + i : -1;
     }
     for (; i < length; i++) if (array[i] === item) return i;
     return -1;