Fix bugs in the _wrapNativeSuper helper (#7533)

* Remove second wrapper from _wrapNativeSuper

* Fix tests on node 4

I DON'T KNOW WHY IT WORKS.

* Update fixtures

* Use Reflect.construct

* Parens

* Fix things

* Fix things

* Undo changes

* Fix with sham

* Typo

packages/babel-helpers/src/helpers.js

@@ -433,14 +433,39 @@ helpers.setPrototypeOf = () => template.program.ast`
 helpers.construct = () => template.program.ast`
   import setPrototypeOf from "setPrototypeOf";
 
+  function isNativeReflectConstruct() {
+    if (typeof Reflect === "undefined" || !Reflect.construct) return false;
+
+    // core-js@3
+    if (Reflect.construct.sham) return false;
+
+    // Proxy can't be polyfilled. Every browser implemented
+    // proxies before or at the same time of Reflect.construct,
+    // so if they support Proxy they also support Reflect.construct.
+    if (typeof Proxy === "function") return true;
+
+    // Since Reflect.construct can't be properly polyfilled, some
+    // implementations (e.g. core-js@2) don't set the correct internal slots.
+    // Those polyfills don't allow us to subclass built-ins, so we need to
+    // use our fallback implementation.
+    try {
+      // If the internal slots aren't set, this throws an error similar to
+      //   TypeError: this is not a Date object.
+      Date.prototype.toString.call(Reflect.construct(Date, [], function() {}));
+      return true;
+    } catch (e) {
+      return false;
+    }
+  }
+
   export default function _construct(Parent, args, Class) {
-    if (typeof Reflect !== "undefined" && Reflect.construct) {
+    if (isNativeReflectConstruct()) {
       _construct = Reflect.construct;
     } else {
       _construct = function _construct(Parent, args, Class) {
         var a = [null];
         a.push.apply(a, args);
-        var Constructor = Parent.bind.apply(Parent, a);
+        var Constructor = Function.bind.apply(Parent, a);
         var instance = new Constructor();
         if (Class) setPrototypeOf(instance, Class.prototype);
         return instance;
@@ -462,6 +487,7 @@ helpers.wrapNativeSuper = () => template.program.ast`
     var _cache = typeof Map === "function" ? new Map() : undefined;
 
     _wrapNativeSuper = function _wrapNativeSuper(Class) {
+      if (Class === null) return null;
       if (typeof Class !== "function") {
         throw new TypeError("Super expression must either be null or a function");
       }
@@ -469,7 +495,9 @@ helpers.wrapNativeSuper = () => template.program.ast`
         if (_cache.has(Class)) return _cache.get(Class);
         _cache.set(Class, Wrapper);
       }
-      function Wrapper() {}
+      function Wrapper() {
+        return _construct(Class, arguments, _gPO(this).constructor)
+      }
       Wrapper.prototype = Object.create(Class.prototype, {
         constructor: {
           value: Wrapper,
@@ -478,15 +506,8 @@ helpers.wrapNativeSuper = () => template.program.ast`
           configurable: true,
         }
       });
-      return _sPO(
-        Wrapper,
-        _sPO(
-          function Super() {
-            return construct(Class, arguments, _gPO(this).constructor);
-          },
-          Class
-        )
-      );
+
+      return _sPO(Wrapper, Class);
     }
 
     return _wrapNativeSuper(Class)

packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/loose/output.js

@@ -1,8 +1,10 @@
 function _inheritsLoose(subClass, superClass) { subClass.prototype.__proto__ = superClass && superClass.prototype; subClass.__proto__ = superClass; }
 
-function _wrapNativeSuper(Class) { var _cache = typeof Map === "function" ? new Map() : undefined; _wrapNativeSuper = function _wrapNativeSuper(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() {} Wrapper.prototype = Object.create(Class.prototype, { constructor: { value: Wrapper, enumerable: false, writable: true, configurable: true } }); return _setPrototypeOf(Wrapper, _setPrototypeOf(function Super() { return _construct(Class, arguments, _getPrototypeOf(this).constructor); }, Class)); }; return _wrapNativeSuper(Class); }
+function _wrapNativeSuper(Class) { var _cache = typeof Map === "function" ? new Map() : undefined; _wrapNativeSuper = function _wrapNativeSuper(Class) { if (Class === null) return null; 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 _construct(Parent, args, Class) { if (typeof Reflect !== "undefined" && Reflect.construct) { _construct = Reflect.construct; } else { _construct = function _construct(Parent, args, Class) { var a = [null]; a.push.apply(a, args); var Constructor = Parent.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 _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 _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }
 

packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/overwritten-null/exec.js

@@ -0,0 +1,9 @@
+var env = {
+  Array: null,
+};
+
+// Wee need to use "with" to avoid leaking the modified Array to other tests.
+with (env) {
+  class List extends Array {}
+  expect(List.prototype.__proto__).toBeUndefined();
+}

packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/overwritten-null/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["transform-classes", "transform-block-scoping"]
+}

packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/spec/output.js

@@ -6,9 +6,11 @@ function _possibleConstructorReturn(self, call) { if (call && (typeof call === "
 
 function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }
 
-function _wrapNativeSuper(Class) { var _cache = typeof Map === "function" ? new Map() : undefined; _wrapNativeSuper = function _wrapNativeSuper(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() {} Wrapper.prototype = Object.create(Class.prototype, { constructor: { value: Wrapper, enumerable: false, writable: true, configurable: true } }); return _setPrototypeOf(Wrapper, _setPrototypeOf(function Super() { return _construct(Class, arguments, _getPrototypeOf(this).constructor); }, Class)); }; return _wrapNativeSuper(Class); }
+function _wrapNativeSuper(Class) { var _cache = typeof Map === "function" ? new Map() : undefined; _wrapNativeSuper = function _wrapNativeSuper(Class) { if (Class === null) return null; 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 _construct(Parent, args, Class) { if (typeof Reflect !== "undefined" && Reflect.construct) { _construct = Reflect.construct; } else { _construct = function _construct(Parent, args, Class) { var a = [null]; a.push.apply(a, args); var Constructor = Parent.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 _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 _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }
 

packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/super-called/exec.js

@@ -0,0 +1,15 @@
+var called = false;
+
+var env = {
+  Array: function Array() {
+    called = true;
+  }
+};
+
+// Wee need to use "with" to avoid leaking the modified Array to other tests.
+with (env) {
+  class List extends Array {};
+  new List();
+
+  expect(called).toBe(true);
+}

packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/super-called/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["transform-classes","transform-block-scoping"]
+}

packages/babel-preset-env/test/fixtures/plugins-integration/issue-7527/exec.js

@@ -4,3 +4,6 @@ class MyDate extends Date {
   }
 }
 let myDate = new MyDate();
+
+expect(myDate.toString).toBe(Date.prototype.toString);
+expect(typeof myDate.toString()).toBe("string");

packages/babel-preset-env/test/fixtures/plugins-integration/issue-7527/output.js

@@ -10,9 +10,11 @@ function _possibleConstructorReturn(self, call) { if (call && (_typeof(call) ===
 
 function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }
 
-function _wrapNativeSuper(Class) { var _cache = typeof Map === "function" ? new Map() : undefined; _wrapNativeSuper = function _wrapNativeSuper(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() {} Wrapper.prototype = Object.create(Class.prototype, { constructor: { value: Wrapper, enumerable: false, writable: true, configurable: true } }); return _setPrototypeOf(Wrapper, _setPrototypeOf(function Super() { return _construct(Class, arguments, _getPrototypeOf(this).constructor); }, Class)); }; return _wrapNativeSuper(Class); }
+function _wrapNativeSuper(Class) { var _cache = typeof Map === "function" ? new Map() : undefined; _wrapNativeSuper = function _wrapNativeSuper(Class) { if (Class === null) return null; 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 _construct(Parent, args, Class) { if (typeof Reflect !== "undefined" && Reflect.construct) { _construct = Reflect.construct; } else { _construct = function _construct(Parent, args, Class) { var a = [null]; a.push.apply(a, args); var Constructor = Parent.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 _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 _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }