Remove old JIT and engine bug guards.

lodash.js

@@ -2824,12 +2824,7 @@
      * @returns {boolean} Returns `true` if `key` exists, else `false`.
      */
     function baseHas(object, key) {
-      // Avoid a bug in IE 10-11 where objects with a [[Prototype]] of `null`,
+      return object != null && hasOwnProperty.call(object, key);
-      // that are composed entirely of index properties, return `false` for
-      // `hasOwnProperty` checks of them.
-      return object != null &&
-        (hasOwnProperty.call(object, key) ||
-          (typeof object == 'object' && key in object && getPrototype(object) === null));
     }
 
     /**
@@ -4004,7 +3999,7 @@
       object = parent(object, path);
 
       var key = toKey(last(path));
-      return !(object != null && baseHas(object, key)) || delete object[key];
+      return !(object != null && hasOwnProperty.call(object, key)) || delete object[key];
     }
 
     /**
@@ -5412,7 +5407,7 @@
       var index = objLength;
       while (index--) {
         var key = objProps[index];
-        if (!(isPartial ? key in other : baseHas(other, key))) {
+        if (!(isPartial ? key in other : hasOwnProperty.call(other, key))) {
           return false;
         }
       }
@@ -5548,19 +5543,6 @@
       return arguments.length ? result(arguments[0], arguments[1]) : result;
     }
 
-    /**
-     * Gets the "length" property value of `object`.
-     *
-     * **Note:** This function is used to avoid a
-     * [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792) that affects
-     * Safari on at least iOS 8.1-8.3 ARM64.
-     *
-     * @private
-     * @param {Object} object The object to query.
-     * @returns {*} Returns the "length" value.
-     */
-    var getLength = baseProperty('length');
-
     /**
      * Gets the data for `map`.
      *
@@ -10888,7 +10870,7 @@
      * // => false
      */
     function isArrayLike(value) {
-      return value != null && isLength(getLength(value)) && !isFunction(value);
+      return value != null && isLength(value.length) && !isFunction(value);
     }
 
     /**
@@ -12838,7 +12820,7 @@
           length = result.length;
 
       for (var key in object) {
-        if (baseHas(object, key) &&
+        if (hasOwnProperty.call(object, key) &&
             !(skipIndexes && (key == 'length' || isIndex(key, length))) &&
             !(isProto && key == 'constructor')) {
           result.push(key);

test/test.js

@@ -5785,26 +5785,6 @@
 
       assert.deepEqual(_.filter(array, isEven), [2]);
     });
-
-    QUnit.test('should iterate over an object with numeric keys (test in Mobile Safari 8)', function(assert) {
-      assert.expect(1);
-
-      // Trigger a mobile Safari 8 JIT bug.
-      // See https://github.com/lodash/lodash/issues/799.
-      var counter = 0,
-          object = { '1': 'foo', '8': 'bar', '50': 'baz' };
-
-      lodashStable.times(1000, function(assert) {
-        _.filter([], stubTrue);
-      });
-
-      _.filter(object, function() {
-        counter++;
-        return true;
-      });
-
-      assert.strictEqual(counter, 3);
-    });
   }());
 
   /*--------------------------------------------------------------------------*/
@@ -7805,19 +7785,6 @@
       }
     });
 
-    QUnit.test('`_.' + methodName + '` should work for objects with a `[[Prototype]]` of `null`', function(assert) {
-      assert.expect(1);
-
-      if (create)  {
-        var object = create(null);
-        object[1] = 'a';
-        assert.strictEqual(func(object, 1), true);
-      }
-      else {
-        skipAssert(assert);
-      }
-    });
-
     QUnit.test('`_.' + methodName + '` should check for a key over a path', function(assert) {
       assert.expect(2);
 
@@ -11238,22 +11205,6 @@
         skipAssert(assert, 7);
       }
     });
-
-    QUnit.test('should avoid V8 bug #2291 (test in Chrome 19-20)', function(assert) {
-      assert.expect(1);
-
-      // Trigger a V8 JIT bug.
-      // See https://code.google.com/p/v8/issues/detail?id=2291.
-      var object = {};
-
-      // First, have a comparison statement.
-      object == object;
-
-      // Then perform the check with `object`.
-      _.isObject(object);
-
-      assert.strictEqual(_.isObject('a'), false);
-    });
   }(1, 2, 3));
 
   /*--------------------------------------------------------------------------*/