move instanceof functionality to separate plugin - fixes #2745

packages/babel-core/test/fixtures/transformation/es6.spec.symbols/instanceof/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["external-helpers-2", "transform-es2015-instanceof"]
+}

packages/babel-helpers/src/helpers.js

@@ -181,7 +181,7 @@ export let inherits = template(`
 
 export let _instanceof = template(`
   (function (left, right) {
-    if (right != null && right[Symbol.hasInstance]) {
+    if (right != null && typeof Symbol !== "undefined" && right[Symbol.hasInstance]) {
       return right[Symbol.hasInstance](left);
     } else {
       return left instanceof right;

packages/babel-plugin-transform-es2015-instanceof/.npmignore

@@ -0,0 +1,3 @@
+src
+test
+node_modules

packages/babel-plugin-transform-es2015-instanceof/package.json

@@ -0,0 +1,14 @@
+{
+  "name": "babel-plugin-transform-es2015-typeof-symbol",
+  "version": "6.0.15",
+  "description": "",
+  "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-typeof-symbol",
+  "license": "MIT",
+  "main": "lib/index.js",
+  "keywords": [
+    "babel-plugin"
+  ],
+  "dependencies": {
+    "babel-runtime": "^5.0.0"
+  }
+}

packages/babel-plugin-transform-es2015-instanceof/src/index.js

@@ -0,0 +1,12 @@
+export default function ({ types: t }) {
+  return {
+    visitor: {
+      BinaryExpression(path) {
+        let { node } = path;
+        if (node.operator === "instanceof") {
+          path.replaceWith(t.callExpression(this.addHelper("instanceof"), [node.left, node.right]));
+        }
+      }
+    }
+  };
+}

packages/babel-plugin-transform-es2015-typeof-symbol/package.json

@@ -1,8 +1,8 @@
 {
-  "name": "babel-plugin-transform-es2015-typeof-symbol",
+  "name": "babel-plugin-transform-es2015-instanceof",
   "version": "6.0.15",
   "description": "",
-  "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-typeof-symbol",
+  "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-es2015-instanceof",
   "license": "MIT",
   "main": "lib/index.js",
   "keywords": [

packages/babel-plugin-transform-es2015-typeof-symbol/src/index.js

@@ -1,9 +1,12 @@
 export default function ({ types: t }) {
+  let IGNORE = Symbol();
+
   return {
     visitor: {
       UnaryExpression(path) {
         let { node, parent } = path;
-        if (node._ignoreSpecSymbols) return;
+        if (node[IGNORE]) return;
+        if (path.find(path => !!path.node._generated)) return;
 
         if (path.parentPath.isBinaryExpression() && t.EQUALITY_BINARY_OPERATORS.indexOf(parent.operator) >= 0) {
           // optimise `typeof foo === "string"` since we can determine that they'll never need to handle symbols
@@ -18,7 +21,7 @@ export default function ({ types: t }) {
           if (path.get("argument").isIdentifier()) {
             let undefLiteral = t.stringLiteral("undefined");
             let unary = t.unaryExpression("typeof", node.argument);
-            unary._ignoreSpecSymbols = true;
+            unary[IGNORE] = true;
             path.replaceWith(t.conditionalExpression(
               t.binaryExpression("===", unary, undefLiteral),
               undefLiteral,
@@ -28,17 +31,6 @@ export default function ({ types: t }) {
             path.replaceWith(call);
           }
         }
-      },
-
-      BinaryExpression(path) {
-        let { node } = path;
-        if (node.operator === "instanceof") {
-          path.replaceWith(t.callExpression(this.addHelper("instanceof"), [node.left, node.right]));
-        }
-      },
-
-      "VariableDeclaration|FunctionDeclaration"(path) {
-        if (path.node._generated) path.skip();
       }
     }
   };