Merge pull request #468 from AluisioASG/core-aliasable

Whitelist constructors aliasable to core-js

lib/6to5/transformation/transformers/optional-core-aliasing.js

@@ -8,6 +8,16 @@ var coreHas = function (node) {
   return node.name !== "_" && _.has(core, node.name);
 };
 
+var ALIASABLE_CONSTRUCTORS = [
+  "Symbol",
+  "Promise",
+  "Map",
+  "WeakMap",
+  "Set",
+  "WeakSet",
+  "Dict",
+];
+
 exports.optional = true;
 
 exports.ast = {
@@ -31,8 +41,8 @@ exports.ast = {
             this.skip();
             return t.prependToMemberExpression(node, file._coreId);
           }
-        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && node.name === "Symbol") {
-          // new Symbol -> new _core.Symbol
+        } else if (t.isIdentifier(node) && !t.isMemberExpression(parent) && t.isReferenced(node, parent) && _.contains(ALIASABLE_CONSTRUCTORS, node.name)) {
+          // Symbol() -> _core.Symbol(); new Promise -> new _core.Promise
           return t.memberExpression(file._coreId, node);
         } else if (t.isCallExpression(node)) {
           // arr[Symbol.iterator]() -> _core.$for.getIterator(arr)

test/fixtures/transformation/optional-core-aliasing/aliased-constructors/actual.js

@@ -0,0 +1,7 @@
+obj.constructor === Object;
+obj.constructor === Promise;
+
+Symbol();
+Symbol("test");
+
+new Map();

test/fixtures/transformation/optional-core-aliasing/aliased-constructors/expected.js

@@ -6,5 +6,10 @@ var _interopRequire = function (obj) {
 
 var _core = _interopRequire(require("core-js/library"));
 
-_core.Symbol("test");
+obj.constructor === Object;
+obj.constructor === _core.Promise;
+
 _core.Symbol();
+_core.Symbol("test");
+
+new _core.Map();

test/fixtures/transformation/optional-core-aliasing/ignore-natives/actual.js

@@ -1 +0,0 @@
-obj.constructor === Object;

test/fixtures/transformation/optional-core-aliasing/ignore-natives/expected.js

@@ -1,9 +0,0 @@
-"use strict";
-
-var _interopRequire = function (obj) {
-  return obj && (obj["default"] || obj);
-};
-
-var _core = _interopRequire(require("core-js/library"));
-
-obj.constructor === Object;

test/fixtures/transformation/optional-core-aliasing/map-symbol/actual.js

@@ -1,2 +0,0 @@
-Symbol("test");
-Symbol();