Setting a property on an object's prototype with function

dist/nested-property.js

@@ -11,17 +11,19 @@ function _typeof(obj) { "@babel/helpers - typeof"; if (typeof Symbol === "functi
 
 function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
 
+function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function"); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, writable: true, configurable: true } }); if (superClass) _setPrototypeOf(subClass, superClass); }
+
+function _createSuper(Derived) { var hasNativeReflectConstruct = _isNativeReflectConstruct(); return function _createSuperInternal() { var Super = _getPrototypeOf(Derived), result; if (hasNativeReflectConstruct) { var NewTarget = _getPrototypeOf(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return _possibleConstructorReturn(this, result); }; }
+
 function _possibleConstructorReturn(self, call) { if (call && (_typeof(call) === "object" || typeof call === "function")) { return call; } return _assertThisInitialized(self); }
 
 function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }
 
-function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function"); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, writable: true, configurable: true } }); if (superClass) _setPrototypeOf(subClass, superClass); }
-
 function _wrapNativeSuper(Class) { var _cache = typeof Map === "function" ? new Map() : undefined; _wrapNativeSuper = function _wrapNativeSuper(Class) { if (Class === null || !_isNativeFunction(Class)) return Class; if (typeof Class !== "function") { throw new TypeError("Super expression must either be null or a function"); } if (typeof _cache !== "undefined") { if (_cache.has(Class)) return _cache.get(Class); _cache.set(Class, Wrapper); } function Wrapper() { return _construct(Class, arguments, _getPrototypeOf(this).constructor); } Wrapper.prototype = Object.create(Class.prototype, { constructor: { value: Wrapper, enumerable: false, writable: true, configurable: true } }); return _setPrototypeOf(Wrapper, Class); }; return _wrapNativeSuper(Class); }
 
-function isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Date.prototype.toString.call(Reflect.construct(Date, [], function () {})); return true; } catch (e) { return false; } }
+function _construct(Parent, args, Class) { if (_isNativeReflectConstruct()) { _construct = Reflect.construct; } else { _construct = function _construct(Parent, args, Class) { var a = [null]; a.push.apply(a, args); var Constructor = Function.bind.apply(Parent, a); var instance = new Constructor(); if (Class) _setPrototypeOf(instance, Class.prototype); return instance; }; } return _construct.apply(null, arguments); }
 
-function _construct(Parent, args, Class) { if (isNativeReflectConstruct()) { _construct = Reflect.construct; } else { _construct = function _construct(Parent, args, Class) { var a = [null]; a.push.apply(a, args); var Constructor = Function.bind.apply(Parent, a); var instance = new Constructor(); if (Class) _setPrototypeOf(instance, Class.prototype); return instance; }; } return _construct.apply(null, arguments); }
+function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Date.prototype.toString.call(Reflect.construct(Date, [], function () {})); return true; } catch (e) { return false; } }
 
 function _isNativeFunction(fn) { return Function.toString.call(fn).indexOf("[native code]") !== -1; }
 
@@ -32,23 +34,23 @@ function _getPrototypeOf(o) { _getPrototypeOf = Object.setPrototypeOf ? Object.g
 var ARRAY_WILDCARD = "+";
 var PATH_DELIMITER = ".";
 
-var ObjectPrototypeMutationError =
-/*#__PURE__*/
-function (_Error) {
+var ObjectPrototypeMutationError = /*#__PURE__*/function (_Error) {
   _inherits(ObjectPrototypeMutationError, _Error);
 
+  var _super = _createSuper(ObjectPrototypeMutationError);
+
   function ObjectPrototypeMutationError(params) {
     var _this;
 
     _classCallCheck(this, ObjectPrototypeMutationError);
 
-    _this = _possibleConstructorReturn(this, _getPrototypeOf(ObjectPrototypeMutationError).call(this, params));
+    _this = _super.call(this, params);
     _this.name = "ObjectPrototypeMutationError";
     return _this;
   }
 
   return ObjectPrototypeMutationError;
-}(_wrapNativeSuper(Error));
+}( /*#__PURE__*/_wrapNativeSuper(Error));
 
 module.exports = {
   set: setNestedProperty,
@@ -159,7 +161,7 @@ function setNestedProperty(object, property, value) {
   }
 
   if (typeof property == "number") {
-    object[property] = value;
+    object[property] = typeof value === "function" ? value(currentObject[currentProperty]) : value;
     return object[property];
   }
 
@@ -181,7 +183,7 @@ function setNestedProperty(object, property, value) {
       }
 
       if (isLastSegment(segments, index)) {
-        currentObject[currentProperty] = value;
+        currentObject[currentProperty] = typeof value === "function" ? value(currentObject[currentProperty]) : value;
       }
 
       return currentObject[currentProperty];

index.js

@@ -124,7 +124,7 @@ function setNestedProperty(object, property, value) {
     }
 
     if (typeof property == "number") {
-        object[property] = value;
+        object[property] = typeof value === "function" ? value(currentObject[currentProperty]) : value;
         return object[property];
     }
 
@@ -146,7 +146,7 @@ function setNestedProperty(object, property, value) {
             }
 
             if (isLastSegment(segments, index)) {
-                currentObject[currentProperty] = value;
+                currentObject[currentProperty] = typeof value === "function" ? value(currentObject[currentProperty]) : value;
             }
 
             return currentObject[currentProperty];

test/set.spec.js

@@ -398,4 +398,24 @@ describe("nested-property.set()", function () {
             }).to.throw(sut.ObjectPrototypeMutationError);
         });
     });
+
+    describe("When setting a property on an object's prototype with function", () => {
+        let newObj, protoObj;
+
+        beforeEach(function () {
+            protoObj = {
+                a: 1
+            };
+            newObj = Object.create(protoObj);
+
+            sut.set(newObj, "__proto__.a", function (value) {
+                return value * 2;
+            });
+        });
+
+        it("Then mutates the prototype", function () {
+            expect(protoObj.hasOwnProperty("a")).to.be.true;
+            expect(protoObj.a).to.be.eql(2);
+        });
+    });
 });