From 7d87e52377b74f159a03fa392a6480296efd5432 Mon Sep 17 00:00:00 2001
From: Sebastian McKenzie <sebmck@gmail.com>
Date: Wed, 25 Feb 2015 17:20:23 +1100
Subject: [PATCH] rejigger strict directives transformer logic so they're
 included in the body before module formatters are ran - @jayphelps

---
 .../transformation/helpers/use-strict.js      | 21 +++++++++++
 .../transformation/transformers/index.js      |  1 +
 .../transformers/internal/declarations.js     | 37 ++++++++++---------
 .../transformers/internal/module-formatter.js |  6 ++-
 .../transformers/internal/use-strict.js       |  9 +++++
 .../transformers/other/use-strict.js          |  4 --
 .../exports-default/expected.js               |  4 +-
 .../es6-modules-amd/exports-from/expected.js  |  4 +-
 .../es6-modules-amd/exports-named/expected.js |  4 +-
 .../exports-variable/expected.js              |  4 +-
 .../get-module-name-option/expected.js        |  6 +--
 .../hoist-function-exports/expected.js        |  4 +-
 .../imports-default/expected.js               |  4 +-
 .../es6-modules-amd/imports-glob/expected.js  |  4 +-
 .../imports-mixing/expected.js                |  4 +-
 .../es6-modules-amd/imports-named/expected.js |  4 +-
 .../es6-modules-amd/imports/expected.js       |  6 +--
 .../es6-modules-amd/module-name/expected.js   |  4 +-
 .../es6-modules-amd/overview/expected.js      |  4 +-
 .../es6-modules-amd/remap/expected.js         |  4 +-
 .../exports-default/expected.js               |  4 +-
 .../exports-from/expected.js                  |  6 +--
 .../exports-generator/expected.js             |  6 +--
 .../exports-named/expected.js                 |  4 +-
 .../exports-variable/expected.js              |  4 +-
 .../get-module-name-option/expected.js        |  6 +--
 .../hoist-function-exports/expected.js        |  4 +-
 .../imports-default/expected.js               |  6 +--
 .../imports-glob/expected.js                  |  6 +--
 .../imports-mixing/expected.js                |  6 +--
 .../imports-named/expected.js                 |  6 +--
 .../es6-modules-system/imports/expected.js    |  6 +--
 .../es6-modules-system/overview/expected.js   |  4 +-
 .../es6-modules-system/remap/expected.js      |  4 +-
 .../exports-default/expected.js               |  4 +-
 .../es6-modules-umd/exports-from/expected.js  |  4 +-
 .../es6-modules-umd/exports-named/expected.js |  4 +-
 .../exports-variable/expected.js              |  4 +-
 .../get-module-name-option/expected.js        |  6 +--
 .../hoist-function-exports/expected.js        |  4 +-
 .../imports-default/expected.js               |  4 +-
 .../es6-modules-umd/imports-glob/expected.js  |  4 +-
 .../imports-mixing/expected.js                |  4 +-
 .../es6-modules-umd/imports-named/expected.js |  4 +-
 .../es6-modules-umd/imports/expected.js       |  6 +--
 .../es6-modules-umd/module-name/expected.js   |  4 +-
 .../es6-modules-umd/overview/expected.js      |  4 +-
 .../es6-modules-umd/remap/expected.js         |  4 +-
 .../runtime/modules-amd/expected.js           |  4 +-
 .../runtime/modules-system/expected.js        |  4 +-
 .../runtime/modules-umd/expected.js           |  6 +--
 51 files changed, 159 insertions(+), 125 deletions(-)
 create mode 100644 lib/babel/transformation/helpers/use-strict.js
 create mode 100644 lib/babel/transformation/transformers/internal/use-strict.js

diff --git a/lib/babel/transformation/helpers/use-strict.js b/lib/babel/transformation/helpers/use-strict.js
new file mode 100644
index 0000000000..7709528a41
--- /dev/null
+++ b/lib/babel/transformation/helpers/use-strict.js
@@ -0,0 +1,21 @@
+"use strict";
+
+var t = require("../../types");
+
+exports.has = function (node) {
+  var first = node.body[0];
+  return t.isExpressionStatement(first) && t.isLiteral(first.expression, { value: "use strict" });
+};
+
+exports.wrap = function (node, callback) {
+  var useStrictNode;
+  if (exports.has(node)) {
+    useStrictNode = node.body.shift();
+  }
+
+  callback();
+
+  if (useStrictNode) {
+    node.body.unshift(useStrictNode);
+  }
+};
diff --git a/lib/babel/transformation/transformers/index.js b/lib/babel/transformation/transformers/index.js
index 4fa7330963..7162c0d066 100644
--- a/lib/babel/transformation/transformers/index.js
+++ b/lib/babel/transformation/transformers/index.js
@@ -95,6 +95,7 @@ module.exports = {
   "spec.typeofSymbol":                     require("./spec/typeof-symbol"),
   "spec.undefinedToVoid":                  require("./spec/undefined-to-void"),
 
+  _useStrict:                              require("./internal/use-strict"),
   _moduleFormatter:                        require("./internal/module-formatter"),
 
   "es3.propertyLiterals":                  require("./es3/property-literals"),
diff --git a/lib/babel/transformation/transformers/internal/declarations.js b/lib/babel/transformation/transformers/internal/declarations.js
index a4297143a4..faa1ca5c54 100644
--- a/lib/babel/transformation/transformers/internal/declarations.js
+++ b/lib/babel/transformation/transformers/internal/declarations.js
@@ -1,6 +1,7 @@
 "use strict";
 
-var t = require("../../../types");
+var useStrict = require("../../helpers/use-strict");
+var t         = require("../../../types");
 
 exports.secondPass = true;
 
@@ -8,26 +9,28 @@ exports.BlockStatement =
 exports.Program = function (node, parent, scope, file) {
   if (!node._declarations) return;
 
-  var kinds = {};
-  var kind;
+  useStrict.wrap(node, function () {
+    var kinds = {};
+    var kind;
 
-  for (var i in node._declarations) {
-    var declar = node._declarations[i];
+    for (var i in node._declarations) {
+      var declar = node._declarations[i];
 
-    kind = declar.kind || "var";
-    var declarNode = t.variableDeclarator(declar.id, declar.init);
+      kind = declar.kind || "var";
+      var declarNode = t.variableDeclarator(declar.id, declar.init);
 
-    if (declar.init) {
-      node.body.unshift(file.attachAuxiliaryComment(t.variableDeclaration(kind, [declarNode])));
-    } else {
-      kinds[kind] = kinds[kind] || [];
-      kinds[kind].push(declarNode);
+      if (declar.init) {
+        node.body.unshift(file.attachAuxiliaryComment(t.variableDeclaration(kind, [declarNode])));
+      } else {
+        kinds[kind] = kinds[kind] || [];
+        kinds[kind].push(declarNode);
+      }
     }
-  }
 
-  for (kind in kinds) {
-    node.body.unshift(file.attachAuxiliaryComment(t.variableDeclaration(kind, kinds[kind])));
-  }
+    for (kind in kinds) {
+      node.body.unshift(file.attachAuxiliaryComment(t.variableDeclaration(kind, kinds[kind])));
+    }
 
-  node._declarations = null;
+    node._declarations = null;
+  });
 };
diff --git a/lib/babel/transformation/transformers/internal/module-formatter.js b/lib/babel/transformation/transformers/internal/module-formatter.js
index 4499ea7bbb..d1982280c4 100644
--- a/lib/babel/transformation/transformers/internal/module-formatter.js
+++ b/lib/babel/transformation/transformers/internal/module-formatter.js
@@ -1,9 +1,13 @@
 "use strict";
 
+var useStrict = require("../../helpers/use-strict");
+
 exports.Program = function (program, parent, scope, file) {
   if (!file.transformers["es6.modules"].canRun()) return;
 
-  program.body = file.dynamicImports.concat(program.body);
+  useStrict.wrap(program, function () {
+    program.body = file.dynamicImports.concat(program.body);
+  });
 
   if (file.moduleFormatter.transform) {
     file.moduleFormatter.transform(program);
diff --git a/lib/babel/transformation/transformers/internal/use-strict.js b/lib/babel/transformation/transformers/internal/use-strict.js
new file mode 100644
index 0000000000..3df31e1c73
--- /dev/null
+++ b/lib/babel/transformation/transformers/internal/use-strict.js
@@ -0,0 +1,9 @@
+"use strict";
+
+var t = require("../../../types");
+
+exports.Program = function (program, parent, scope, file) {
+  if (file.transformers.useStrict.canRun()) {
+    program.body.unshift(t.expressionStatement(t.literal("use strict")));
+  }
+};
diff --git a/lib/babel/transformation/transformers/other/use-strict.js b/lib/babel/transformation/transformers/other/use-strict.js
index 5ce37145f8..dc864770e8 100644
--- a/lib/babel/transformation/transformers/other/use-strict.js
+++ b/lib/babel/transformation/transformers/other/use-strict.js
@@ -10,10 +10,6 @@ exports.Program = function (program) {
   }
 };
 
-exports.post = function (file) {
-  file.ast.program.body.unshift(t.expressionStatement(t.literal("use strict")));
-};
-
 exports.FunctionDeclaration =
 exports.FunctionExpression = function () {
   this.skip();
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-default/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-default/expected.js
index 371d42a3ac..ea14e00737 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-default/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports", "module"], function (exports, module) {
+  "use strict";
+
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
   module.exports = foo;
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
index ed602a6536..113dd40be3 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-from/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports", "foo"], function (exports, _foo) {
+  "use strict";
+
   var _interopRequireWildcard = function (obj) { return obj && obj.__esModule ? obj : { "default": obj }; };
 
   var _defaults = function (obj, defaults) { var keys = Object.getOwnPropertyNames(defaults); for (var i = 0; i < keys.length; i++) { var key = keys[i]; var value = Object.getOwnPropertyDescriptor(defaults, key); if (value && value.configurable && obj[key] === undefined) { Object.defineProperty(obj, key, value); } } return obj; };
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-named/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-named/expected.js
index 84d448ff9c..d66e609acb 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-named/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports"], function (exports) {
+  "use strict";
+
   exports.foo = foo;
   exports.foo = foo;
   exports.bar = bar;
diff --git a/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
index 78d201535b..9f4243860d 100644
--- a/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/exports-variable/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports"], function (exports) {
+  "use strict";
+
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
   exports.foo7 = foo7;
diff --git a/test/fixtures/transformation/es6-modules-amd/get-module-name-option/expected.js b/test/fixtures/transformation/es6-modules-amd/get-module-name-option/expected.js
index b06fd3928a..4a88732e99 100644
--- a/test/fixtures/transformation/es6-modules-amd/get-module-name-option/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/get-module-name-option/expected.js
@@ -1,3 +1,3 @@
-"use strict";
-
-define("my custom module name", ["exports"], function (exports) {});
\ No newline at end of file
+define("my custom module name", ["exports"], function (exports) {
+  "use strict";
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/hoist-function-exports/expected.js b/test/fixtures/transformation/es6-modules-amd/hoist-function-exports/expected.js
index 058d009ac2..79267d3f30 100644
--- a/test/fixtures/transformation/es6-modules-amd/hoist-function-exports/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/hoist-function-exports/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports", "./evens"], function (exports, _evens) {
+  "use strict";
+
   exports.nextOdd = nextOdd;
   var isEven = _evens.isEven;
   function nextOdd(n) {
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
index 167222ee75..4575943441 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-default/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports", "foo"], function (exports, _foo) {
+  "use strict";
+
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-glob/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-glob/expected.js
index 4788c80508..cc03946787 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-glob/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-glob/expected.js
@@ -1,5 +1,5 @@
-"use strict";
-
 define(["exports", "foo"], function (exports, _foo) {
+  "use strict";
+
   var foo = _foo;
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
index 59164e1d1f..b147224a07 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-mixing/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports", "foo"], function (exports, _foo) {
+  "use strict";
+
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-amd/imports-named/expected.js b/test/fixtures/transformation/es6-modules-amd/imports-named/expected.js
index 8e5e4a9e81..0b46440074 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports-named/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports", "foo"], function (exports, _foo) {
+  "use strict";
+
   var bar = _foo.bar;
   var bar2 = _foo.bar2;
   var baz = _foo.baz;
diff --git a/test/fixtures/transformation/es6-modules-amd/imports/expected.js b/test/fixtures/transformation/es6-modules-amd/imports/expected.js
index 36ff98ebcc..84e1e6dcc7 100644
--- a/test/fixtures/transformation/es6-modules-amd/imports/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/imports/expected.js
@@ -1,3 +1,3 @@
-"use strict";
-
-define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {});
\ No newline at end of file
+define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
+  "use strict";
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/module-name/expected.js b/test/fixtures/transformation/es6-modules-amd/module-name/expected.js
index 5c6619dc82..c129a9ffb6 100644
--- a/test/fixtures/transformation/es6-modules-amd/module-name/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/module-name/expected.js
@@ -1,5 +1,5 @@
-"use strict";
-
 define("es6-modules-amd/module-name/expected", ["exports"], function (exports) {
+  "use strict";
+
   foobar();
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-amd/overview/expected.js b/test/fixtures/transformation/es6-modules-amd/overview/expected.js
index 28fa5347fa..a9993c1612 100644
--- a/test/fixtures/transformation/es6-modules-amd/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/overview/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports", "foo", "foo-bar", "./directory/foo-bar"], function (exports, _foo, _fooBar, _directoryFooBar) {
+  "use strict";
+
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-amd/remap/expected.js b/test/fixtures/transformation/es6-modules-amd/remap/expected.js
index 0fe9ee14d8..accde1fb6e 100644
--- a/test/fixtures/transformation/es6-modules-amd/remap/expected.js
+++ b/test/fixtures/transformation/es6-modules-amd/remap/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports"], function (exports) {
+  "use strict";
+
   var test = exports.test = 2;
   test = exports.test = 5;
   test = exports.test += 1;
diff --git a/test/fixtures/transformation/es6-modules-system/exports-default/expected.js b/test/fixtures/transformation/es6-modules-system/exports-default/expected.js
index 9fa1b7604a..f6442f9402 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-default/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register([], function (_export) {
   var _classCallCheck, _default, Foo;
 
@@ -9,6 +7,8 @@ System.register([], function (_export) {
   return {
     setters: [],
     execute: function () {
+      "use strict";
+
       _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
       _export("default", 42);
diff --git a/test/fixtures/transformation/es6-modules-system/exports-from/expected.js b/test/fixtures/transformation/es6-modules-system/exports-from/expected.js
index 389dfc41ae..c1eaca763d 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-from/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register(["foo"], function (_export) {
   return {
     setters: [function (_foo) {
@@ -21,6 +19,8 @@ System.register(["foo"], function (_export) {
 
       _export("bar", _foo.bar);
     }],
-    execute: function () {}
+    execute: function () {
+      "use strict";
+    }
   };
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/exports-generator/expected.js b/test/fixtures/transformation/es6-modules-system/exports-generator/expected.js
index b7ae39a4d7..e4af9b4163 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-generator/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-generator/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register([], function (_export) {
   var generator = regeneratorRuntime.mark(function generator() {
     return regeneratorRuntime.wrap(function generator$(context$1$0) {
@@ -19,6 +17,8 @@ System.register([], function (_export) {
 
   return {
     setters: [],
-    execute: function () {}
+    execute: function () {
+      "use strict";
+    }
   };
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/exports-named/expected.js b/test/fixtures/transformation/es6-modules-system/exports-named/expected.js
index e332163eba..410345bcfa 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-named/expected.js
@@ -1,9 +1,9 @@
-"use strict";
-
 System.register([], function (_export) {
   return {
     setters: [],
     execute: function () {
+      "use strict";
+
       _export("foo", foo);
 
       _export("foo", foo);
diff --git a/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
index 9ada1fff32..8e7893b129 100644
--- a/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/exports-variable/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register([], function (_export) {
   var _classCallCheck, foo, foo2, foo3, foo4, foo5, foo6, foo8;
 
@@ -9,6 +7,8 @@ System.register([], function (_export) {
   return {
     setters: [],
     execute: function () {
+      "use strict";
+
       _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
       foo = _export("foo", 1);
diff --git a/test/fixtures/transformation/es6-modules-system/get-module-name-option/expected.js b/test/fixtures/transformation/es6-modules-system/get-module-name-option/expected.js
index bd650c0abc..0f7fc369ae 100644
--- a/test/fixtures/transformation/es6-modules-system/get-module-name-option/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/get-module-name-option/expected.js
@@ -1,8 +1,8 @@
-"use strict";
-
 System.register("my custom module name", [], function (_export) {
   return {
     setters: [],
-    execute: function () {}
+    execute: function () {
+      "use strict";
+    }
   };
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/hoist-function-exports/expected.js b/test/fixtures/transformation/es6-modules-system/hoist-function-exports/expected.js
index 553b69fe58..0e4643803d 100644
--- a/test/fixtures/transformation/es6-modules-system/hoist-function-exports/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/hoist-function-exports/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register(["./evens"], function (_export) {
   var isEven, p, isOdd;
 
@@ -14,6 +12,8 @@ System.register(["./evens"], function (_export) {
       isEven = _evens.isEven;
     }],
     execute: function () {
+      "use strict";
+
       p = _export("p", 5);
       isOdd = _export("isOdd", (function (isEven) {
         return function (n) {
diff --git a/test/fixtures/transformation/es6-modules-system/imports-default/expected.js b/test/fixtures/transformation/es6-modules-system/imports-default/expected.js
index 12696f6653..2cb90409c2 100644
--- a/test/fixtures/transformation/es6-modules-system/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports-default/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register(["foo"], function (_export) {
   var foo, foo2;
   return {
@@ -7,6 +5,8 @@ System.register(["foo"], function (_export) {
       foo = _foo["default"];
       foo2 = _foo["default"];
     }],
-    execute: function () {}
+    execute: function () {
+      "use strict";
+    }
   };
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/imports-glob/expected.js b/test/fixtures/transformation/es6-modules-system/imports-glob/expected.js
index acd0e1efcf..67e60e45ca 100644
--- a/test/fixtures/transformation/es6-modules-system/imports-glob/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports-glob/expected.js
@@ -1,11 +1,11 @@
-"use strict";
-
 System.register(["foo"], function (_export) {
   var foo;
   return {
     setters: [function (_foo) {
       foo = _foo;
     }],
-    execute: function () {}
+    execute: function () {
+      "use strict";
+    }
   };
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-system/imports-mixing/expected.js
index 7e4f71269d..9ac0cd5ce2 100644
--- a/test/fixtures/transformation/es6-modules-system/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports-mixing/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register(["foo"], function (_export) {
   var foo, xyz;
   return {
@@ -7,6 +5,8 @@ System.register(["foo"], function (_export) {
       foo = _foo["default"];
       xyz = _foo.baz;
     }],
-    execute: function () {}
+    execute: function () {
+      "use strict";
+    }
   };
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/imports-named/expected.js b/test/fixtures/transformation/es6-modules-system/imports-named/expected.js
index 9b8eb605bf..b66550bded 100644
--- a/test/fixtures/transformation/es6-modules-system/imports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports-named/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register(["foo"], function (_export) {
   var bar, bar2, baz, baz2, baz3, xyz;
   return {
@@ -11,6 +9,8 @@ System.register(["foo"], function (_export) {
       baz3 = _foo.bar;
       xyz = _foo.xyz;
     }],
-    execute: function () {}
+    execute: function () {
+      "use strict";
+    }
   };
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/imports/expected.js b/test/fixtures/transformation/es6-modules-system/imports/expected.js
index dcd2757e57..2b02e610fc 100644
--- a/test/fixtures/transformation/es6-modules-system/imports/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/imports/expected.js
@@ -1,8 +1,8 @@
-"use strict";
-
 System.register(["foo", "foo-bar", "./directory/foo-bar"], function (_export) {
   return {
     setters: [function (_foo) {}, function (_fooBar) {}, function (_directoryFooBar) {}],
-    execute: function () {}
+    execute: function () {
+      "use strict";
+    }
   };
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-system/overview/expected.js b/test/fixtures/transformation/es6-modules-system/overview/expected.js
index d7a161df9f..c8e042ef50 100644
--- a/test/fixtures/transformation/es6-modules-system/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/overview/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register(["foo", "foo-bar", "./directory/foo-bar"], function (_export) {
   var foo, foo2, bar, bar2, test2;
   return {
@@ -10,6 +8,8 @@ System.register(["foo", "foo-bar", "./directory/foo-bar"], function (_export) {
       bar2 = _foo.foo;
     }, function (_fooBar) {}, function (_directoryFooBar) {}],
     execute: function () {
+      "use strict";
+
       _export("test", test);
 
       test2 = _export("test2", 5);
diff --git a/test/fixtures/transformation/es6-modules-system/remap/expected.js b/test/fixtures/transformation/es6-modules-system/remap/expected.js
index 75dfba18e2..16a16011c6 100644
--- a/test/fixtures/transformation/es6-modules-system/remap/expected.js
+++ b/test/fixtures/transformation/es6-modules-system/remap/expected.js
@@ -1,10 +1,10 @@
-"use strict";
-
 System.register([], function (_export) {
   var test;
   return {
     setters: [],
     execute: function () {
+      "use strict";
+
       test = _export("test", 2);
 
       _export("test", test = 5);
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-default/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-default/expected.js
index dea3d841ba..7395d1a5f7 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-default/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "module"], factory);
@@ -7,6 +5,8 @@
     factory(exports, module);
   }
 })(function (exports, module) {
+  "use strict";
+
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
   module.exports = foo;
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
index 022983fc7b..35cdb100e3 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-from/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -7,6 +5,8 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
+  "use strict";
+
   var _interopRequireWildcard = function (obj) { return obj && obj.__esModule ? obj : { "default": obj }; };
 
   var _defaults = function (obj, defaults) { var keys = Object.getOwnPropertyNames(defaults); for (var i = 0; i < keys.length; i++) { var key = keys[i]; var value = Object.getOwnPropertyDescriptor(defaults, key); if (value && value.configurable && obj[key] === undefined) { Object.defineProperty(obj, key, value); } } return obj; };
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-named/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-named/expected.js
index a894d9a509..3b4d067ec0 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-named/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports"], factory);
@@ -7,6 +5,8 @@
     factory(exports);
   }
 })(function (exports) {
+  "use strict";
+
   exports.foo = foo;
   exports.foo = foo;
   exports.bar = bar;
diff --git a/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js b/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
index 828ae59ea0..abd2b1fee0 100644
--- a/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/exports-variable/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports"], factory);
@@ -7,6 +5,8 @@
     factory(exports);
   }
 })(function (exports) {
+  "use strict";
+
   var _classCallCheck = function (instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } };
 
   exports.foo7 = foo7;
diff --git a/test/fixtures/transformation/es6-modules-umd/get-module-name-option/expected.js b/test/fixtures/transformation/es6-modules-umd/get-module-name-option/expected.js
index bd0e644592..ceb362161c 100644
--- a/test/fixtures/transformation/es6-modules-umd/get-module-name-option/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/get-module-name-option/expected.js
@@ -1,9 +1,9 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define("my custom module name", ["exports"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports);
   }
-})(function (exports) {});
\ No newline at end of file
+})(function (exports) {
+  "use strict";
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/hoist-function-exports/expected.js b/test/fixtures/transformation/es6-modules-umd/hoist-function-exports/expected.js
index 09d47d6c27..1241f1f68e 100644
--- a/test/fixtures/transformation/es6-modules-umd/hoist-function-exports/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/hoist-function-exports/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "./evens"], factory);
@@ -7,6 +5,8 @@
     factory(exports, require("./evens"));
   }
 })(function (exports, _evens) {
+  "use strict";
+
   exports.nextOdd = nextOdd;
   var isEven = _evens.isEven;
   function nextOdd(n) {
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
index 17c0bb534c..46111b877c 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-default/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -7,6 +5,8 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
+  "use strict";
+
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-glob/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-glob/expected.js
index 067a1a2714..45a763f2f2 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-glob/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-glob/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -7,5 +5,7 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
+  "use strict";
+
   var foo = _foo;
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
index 5de8931b9b..6b684e31de 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-mixing/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -7,6 +5,8 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
+  "use strict";
+
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-umd/imports-named/expected.js b/test/fixtures/transformation/es6-modules-umd/imports-named/expected.js
index 3e4f5746d9..22062a454c 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports-named/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports-named/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo"], factory);
@@ -7,6 +5,8 @@
     factory(exports, require("foo"));
   }
 })(function (exports, _foo) {
+  "use strict";
+
   var bar = _foo.bar;
   var bar2 = _foo.bar2;
   var baz = _foo.baz;
diff --git a/test/fixtures/transformation/es6-modules-umd/imports/expected.js b/test/fixtures/transformation/es6-modules-umd/imports/expected.js
index 29cf8095a7..2e39b15cd2 100644
--- a/test/fixtures/transformation/es6-modules-umd/imports/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/imports/expected.js
@@ -1,9 +1,9 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
   } else if (typeof exports !== "undefined") {
     factory(exports, require("foo"), require("foo-bar"), require("./directory/foo-bar"));
   }
-})(function (exports, _foo, _fooBar, _directoryFooBar) {});
\ No newline at end of file
+})(function (exports, _foo, _fooBar, _directoryFooBar) {
+  "use strict";
+});
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/module-name/expected.js b/test/fixtures/transformation/es6-modules-umd/module-name/expected.js
index 193a600c46..aa570b25e3 100644
--- a/test/fixtures/transformation/es6-modules-umd/module-name/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/module-name/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define("es6-modules-umd/module-name/expected", ["exports"], factory);
@@ -7,5 +5,7 @@
     factory(exports);
   }
 })(function (exports) {
+  "use strict";
+
   foobar();
 });
\ No newline at end of file
diff --git a/test/fixtures/transformation/es6-modules-umd/overview/expected.js b/test/fixtures/transformation/es6-modules-umd/overview/expected.js
index 821fab6755..8f0262a8ee 100644
--- a/test/fixtures/transformation/es6-modules-umd/overview/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/overview/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo", "foo-bar", "./directory/foo-bar"], factory);
@@ -7,6 +5,8 @@
     factory(exports, require("foo"), require("foo-bar"), require("./directory/foo-bar"));
   }
 })(function (exports, _foo, _fooBar, _directoryFooBar) {
+  "use strict";
+
   var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };
 
   var foo = _interopRequire(_foo);
diff --git a/test/fixtures/transformation/es6-modules-umd/remap/expected.js b/test/fixtures/transformation/es6-modules-umd/remap/expected.js
index 82882dde3f..e44f8e70c5 100644
--- a/test/fixtures/transformation/es6-modules-umd/remap/expected.js
+++ b/test/fixtures/transformation/es6-modules-umd/remap/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports"], factory);
@@ -7,6 +5,8 @@
     factory(exports);
   }
 })(function (exports) {
+  "use strict";
+
   var test = exports.test = 2;
   test = exports.test = 5;
   test = exports.test += 1;
diff --git a/test/fixtures/transformation/runtime/modules-amd/expected.js b/test/fixtures/transformation/runtime/modules-amd/expected.js
index 9db3f81296..ef9e316cb0 100644
--- a/test/fixtures/transformation/runtime/modules-amd/expected.js
+++ b/test/fixtures/transformation/runtime/modules-amd/expected.js
@@ -1,6 +1,6 @@
-"use strict";
-
 define(["exports", "foo", "babel-runtime/helpers"], function (exports, _foo, _babelRuntimeHelpers) {
+  "use strict";
+
   var _babelHelpers = _babelRuntimeHelpers["default"];
 
   var foo = _babelHelpers.interopRequire(_foo);
diff --git a/test/fixtures/transformation/runtime/modules-system/expected.js b/test/fixtures/transformation/runtime/modules-system/expected.js
index 526b72c64d..cdd6623fbf 100644
--- a/test/fixtures/transformation/runtime/modules-system/expected.js
+++ b/test/fixtures/transformation/runtime/modules-system/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 System.register(["babel-runtime/helpers"], function (_export) {
   var _babelHelpers;
 
@@ -8,6 +6,8 @@ System.register(["babel-runtime/helpers"], function (_export) {
       _babelHelpers = _babelRuntimeHelpers["default"];
     }],
     execute: function () {
+      "use strict";
+
       foo.apply(undefined, _babelHelpers.toConsumableArray(bar));
     }
   };
diff --git a/test/fixtures/transformation/runtime/modules-umd/expected.js b/test/fixtures/transformation/runtime/modules-umd/expected.js
index d380c97e69..5868c4ac04 100644
--- a/test/fixtures/transformation/runtime/modules-umd/expected.js
+++ b/test/fixtures/transformation/runtime/modules-umd/expected.js
@@ -1,5 +1,3 @@
-"use strict";
-
 (function (factory) {
   if (typeof define === "function" && define.amd) {
     define(["exports", "foo", "babel-runtime/helpers"], factory);
@@ -7,7 +5,9 @@
     factory(exports, require("foo"), require("babel-runtime/helpers"));
   }
 })(function (exports, _foo, _babelRuntimeHelpers) {
+  "use strict";
+
   var _babelHelpers = _babelRuntimeHelpers["default"];
 
   var foo = _babelHelpers.interopRequire(_foo);
-});
+});
\ No newline at end of file