Ensure baseAt, basePullAt, and pullAt handle nullish values correctly.

lodash.src.js

@@ -1829,8 +1829,9 @@
      */
     function baseAt(collection, props) {
       var index = -1,
-          isArr = isArrayLike(collection),
-          length = collection.length,
+          isNil = collection == null,
+          isArr = !isNil && isArrayLike(collection),
+          length = isArr && collection.length,
           propsLength = props.length,
           result = Array(propsLength);
 
@@ -1839,7 +1840,7 @@
         if (isArr) {
           result[index] = isIndex(key, length) ? collection[key] : undefined;
         } else {
-          result[index] = collection[key];
+          result[index] = isNil ? undefined : collection[key];
         }
       }
       return result;
@@ -2711,7 +2712,7 @@
      * @returns {Array} Returns `array`.
      */
     function basePullAt(array, indexes) {
-      var length = indexes.length;
+      var length = array ? indexes.length : 0;
       while (length--) {
         var index = parseFloat(indexes[length]);
         if (index != previous && isIndex(index)) {
@@ -5476,7 +5477,6 @@
      * // => [10, 20]
      */
     var pullAt = restParam(function(array, indexes) {
-      array || (array = []);
       indexes = baseFlatten(indexes);
 
       var result = baseAt(array, indexes);

test/test.js

@@ -1219,11 +1219,11 @@
     });
 
     test('should work with a falsey `collection` argument when keys are provided', 1, function() {
-      var expected = _.map(falsey, _.constant([undefined, undefined]));
+      var expected = _.map(falsey, _.constant(Array(4)));
 
       var actual = _.map(falsey, function(value) {
         try {
-          return _.at(value, 0, 1);
+          return _.at(value, 0, 1, 'pop', 'push');
         } catch(e) {}
       });
 
@@ -4456,7 +4456,7 @@
       var array = [1, 2, 3],
           actual = _.fill(array);
 
-      deepEqual(actual, [undefined, undefined, undefined]);
+      deepEqual(actual, Array(3));
       ok(_.every(actual, function(value, index) { return index in actual; }));
     });
 
@@ -12467,7 +12467,7 @@
 
       var values = _.reject(empties, function(value) {
         return value === 0 || _.isArray(value);
-      }).concat(-1, 1.1);
+      }).concat(-1, 1.1, 'pop', 'push');
 
       var expected = _.map(values, _.constant(undefined)),
           actual = _.pullAt(array, values);
@@ -12506,11 +12506,11 @@
     });
 
     test('should work with a falsey `array` argument when keys are provided', 1, function() {
-      var expected = _.map(falsey, _.constant([undefined, undefined]));
+      var expected = _.map(falsey, _.constant(Array(4)));
 
       var actual = _.map(falsey, function(value) {
         try {
-          return _.pullAt(value, 0, 1);
+          return _.pullAt(value, 0, 1, 'pop', 'push');
         } catch(e) {}
       });