Fix _isNaiveReflectConstruct helper

Date#toString is generic in ES2015 [1] and it doesn't throw, so we also check Map#get (which on the other hand doesn't exist in ES5 browsers). [1]: tc39/ecma262#1268 (comment)
babel · Aug 13, 2018 · 3d7873e · 3d7873e
1 parent de16ac0
commit 3d7873e
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Showing 4 changed files with 11 additions and 3 deletions.
diff --git a/packages/babel-helpers/src/helpers.js b/packages/babel-helpers/src/helpers.js
@@ -472,7 +472,15 @@ helpers.construct = helper("7.0.0-beta.0")`
     try {
       // If the internal slots aren't set, this throws an error similar to
       //   TypeError: this is not a Date object.
+      // Date#toString is generic in ES2015 [1] and it doesn't throw, so we also
+      // check Map#get (which on the other hand doesn't exist in ES5 browsers).
+      //
+      // [1]: https://github.com/tc39/ecma262/issues/1268#issuecomment-410104832
+
       Date.prototype.toString.call(Reflect.construct(Date, [], function() {}));
+      if (typeof Map === "function") {
+        Map.prototype.get.call(Reflect.construct(Map, [], function() {}));
+      }
       return true;
     } catch (e) {
       return false;

diff --git a/packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/loose/output.js b/packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/loose/output.js
@@ -2,7 +2,7 @@ function _inheritsLoose(subClass, superClass) { subClass.prototype = Object.crea
 
 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 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 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 () {})); if (typeof Map === "function") { Map.prototype.get.call(Reflect.construct(Map, [], 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); }
 

diff --git a/packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/spec/output.js b/packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/spec/output.js
@@ -8,7 +8,7 @@ function _inherits(subClass, superClass) { if (typeof superClass !== "function"
 
 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 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 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 () {})); if (typeof Map === "function") { Map.prototype.get.call(Reflect.construct(Map, [], 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); }
 

diff --git a/packages/babel-preset-env/test/fixtures/plugins-integration/issue-7527/output.js b/packages/babel-preset-env/test/fixtures/plugins-integration/issue-7527/output.js
@@ -12,7 +12,7 @@ function _inherits(subClass, superClass) { if (typeof superClass !== "function"
 
 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 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 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 () {})); if (typeof Map === "function") { Map.prototype.get.call(Reflect.construct(Map, [], 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); }