diff --git a/src/compiler/emitter.ts b/src/compiler/emitter.ts
index fd0d4ad796e5d..cd827a54c5196 100644
--- a/src/compiler/emitter.ts
+++ b/src/compiler/emitter.ts
@@ -3012,6 +3012,26 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                 return result;
             }
 
+            function emitEs6ExportDefaultCompat(node: Node) {
+                if (node.parent.kind === SyntaxKind.SourceFile) {
+                    Debug.assert(!!(node.flags & NodeFlags.Default) || node.kind === SyntaxKind.ExportAssignment);
+                    // only allow export default at a source file level
+                    if (compilerOptions.module === ModuleKind.CommonJS || compilerOptions.module === ModuleKind.AMD || compilerOptions.module === ModuleKind.UMD) {
+                        if (!currentSourceFile.symbol.exports["___esModule"]) {
+                            if (languageVersion === ScriptTarget.ES5) {
+                                // default value of configurable, enumerable, writable are `false`. 
+                                write("Object.defineProperty(exports, \"__esModule\", { value: true });");
+                                writeLine();
+                            }
+                            else if (languageVersion === ScriptTarget.ES3) {
+                                write("exports.__esModule = true;");
+                                writeLine();
+                            }
+                        }
+                    }
+                }
+            }
+
             function emitExportMemberAssignment(node: FunctionLikeDeclaration | ClassDeclaration) {
                 if (node.flags & NodeFlags.Export) {
                     writeLine();
@@ -3034,9 +3054,11 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                     }
                     else {
                         if (node.flags & NodeFlags.Default) {
+                            emitEs6ExportDefaultCompat(node);
                             if (languageVersion === ScriptTarget.ES3) {
                                 write("exports[\"default\"]");
-                            } else {
+                            }
+                            else {
                                 write("exports.default");
                             }
                         }
@@ -5529,6 +5551,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
                             write(")");
                         }
                         else {
+                            emitEs6ExportDefaultCompat(node);
                             emitContainingModuleName(node);
                             if (languageVersion === ScriptTarget.ES3) {
                                 write("[\"default\"] = ");
diff --git a/tests/baselines/reference/es5-commonjs.js b/tests/baselines/reference/es5-commonjs.js
new file mode 100644
index 0000000000000..2a0c6d924ca49
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs.js
@@ -0,0 +1,27 @@
+//// [es5-commonjs.ts]
+
+export default class A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+    {
+        return 42;
+    }
+}
+
+
+//// [es5-commonjs.js]
+var A = (function () {
+    function A() {
+    }
+    A.prototype.B = function () {
+        return 42;
+    };
+    return A;
+})();
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.default = A;
diff --git a/tests/baselines/reference/es5-commonjs.symbols b/tests/baselines/reference/es5-commonjs.symbols
new file mode 100644
index 0000000000000..41e4484afcde9
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs.symbols
@@ -0,0 +1,17 @@
+=== tests/cases/compiler/es5-commonjs.ts ===
+
+export default class A
+>A : Symbol(A, Decl(es5-commonjs.ts, 0, 0))
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+>B : Symbol(B, Decl(es5-commonjs.ts, 6, 5))
+    {
+        return 42;
+    }
+}
+
diff --git a/tests/baselines/reference/es5-commonjs.types b/tests/baselines/reference/es5-commonjs.types
new file mode 100644
index 0000000000000..4c1bc9229177f
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs.types
@@ -0,0 +1,18 @@
+=== tests/cases/compiler/es5-commonjs.ts ===
+
+export default class A
+>A : A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+>B : () => number
+    {
+        return 42;
+>42 : number
+    }
+}
+
diff --git a/tests/baselines/reference/es5-commonjs2.js b/tests/baselines/reference/es5-commonjs2.js
new file mode 100644
index 0000000000000..174665b41255a
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs2.js
@@ -0,0 +1,8 @@
+//// [es5-commonjs2.ts]
+
+export default 1;
+
+
+//// [es5-commonjs2.js]
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.default = 1;
diff --git a/tests/baselines/reference/es5-commonjs2.symbols b/tests/baselines/reference/es5-commonjs2.symbols
new file mode 100644
index 0000000000000..ee57f9ad5cdad
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs2.symbols
@@ -0,0 +1,5 @@
+=== tests/cases/compiler/es5-commonjs2.ts ===
+
+No type information for this code.export default 1;
+No type information for this code.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/es5-commonjs2.types b/tests/baselines/reference/es5-commonjs2.types
new file mode 100644
index 0000000000000..ee57f9ad5cdad
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs2.types
@@ -0,0 +1,5 @@
+=== tests/cases/compiler/es5-commonjs2.ts ===
+
+No type information for this code.export default 1;
+No type information for this code.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/es5-commonjs3.js b/tests/baselines/reference/es5-commonjs3.js
new file mode 100644
index 0000000000000..cc3d0b1527a2a
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs3.js
@@ -0,0 +1,9 @@
+//// [es5-commonjs3.ts]
+
+export default "test";
+export var __esModule = 1;
+
+
+//// [es5-commonjs3.js]
+exports.default = "test";
+exports.__esModule = 1;
diff --git a/tests/baselines/reference/es5-commonjs3.symbols b/tests/baselines/reference/es5-commonjs3.symbols
new file mode 100644
index 0000000000000..9d5bc830099e8
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs3.symbols
@@ -0,0 +1,6 @@
+=== tests/cases/compiler/es5-commonjs3.ts ===
+
+export default "test";
+export var __esModule = 1;
+>__esModule : Symbol(__esModule, Decl(es5-commonjs3.ts, 2, 10))
+
diff --git a/tests/baselines/reference/es5-commonjs3.types b/tests/baselines/reference/es5-commonjs3.types
new file mode 100644
index 0000000000000..facdfae00ce94
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs3.types
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/es5-commonjs3.ts ===
+
+export default "test";
+export var __esModule = 1;
+>__esModule : number
+>1 : number
+
diff --git a/tests/baselines/reference/es5-commonjs4.js b/tests/baselines/reference/es5-commonjs4.js
new file mode 100644
index 0000000000000..50a4c49e464f3
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs4.js
@@ -0,0 +1,28 @@
+//// [es5-commonjs4.ts]
+
+export default class A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+    {
+        return 42;
+    }
+}
+export var __esModule = 1;
+
+
+//// [es5-commonjs4.js]
+var A = (function () {
+    function A() {
+    }
+    A.prototype.B = function () {
+        return 42;
+    };
+    return A;
+})();
+exports.default = A;
+exports.__esModule = 1;
diff --git a/tests/baselines/reference/es5-commonjs4.symbols b/tests/baselines/reference/es5-commonjs4.symbols
new file mode 100644
index 0000000000000..22d41128d7411
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs4.symbols
@@ -0,0 +1,19 @@
+=== tests/cases/compiler/es5-commonjs4.ts ===
+
+export default class A
+>A : Symbol(A, Decl(es5-commonjs4.ts, 0, 0))
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+>B : Symbol(B, Decl(es5-commonjs4.ts, 6, 5))
+    {
+        return 42;
+    }
+}
+export var __esModule = 1;
+>__esModule : Symbol(__esModule, Decl(es5-commonjs4.ts, 13, 10))
+
diff --git a/tests/baselines/reference/es5-commonjs4.types b/tests/baselines/reference/es5-commonjs4.types
new file mode 100644
index 0000000000000..d3471afbfeb52
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs4.types
@@ -0,0 +1,21 @@
+=== tests/cases/compiler/es5-commonjs4.ts ===
+
+export default class A
+>A : A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+>B : () => number
+    {
+        return 42;
+>42 : number
+    }
+}
+export var __esModule = 1;
+>__esModule : number
+>1 : number
+
diff --git a/tests/baselines/reference/es5-commonjs5.js b/tests/baselines/reference/es5-commonjs5.js
new file mode 100644
index 0000000000000..ead6079eff13e
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs5.js
@@ -0,0 +1,13 @@
+//// [es5-commonjs5.ts]
+
+export default function () {
+	return "test";
+}
+
+
+//// [es5-commonjs5.js]
+function default_1() {
+    return "test";
+}
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.default = default_1;
diff --git a/tests/baselines/reference/es5-commonjs5.symbols b/tests/baselines/reference/es5-commonjs5.symbols
new file mode 100644
index 0000000000000..b134e21666834
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs5.symbols
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/es5-commonjs5.ts ===
+
+No type information for this code.export default function () {
+No type information for this code.	return "test";
+No type information for this code.}
+No type information for this code.
+No type information for this code.
\ No newline at end of file
diff --git a/tests/baselines/reference/es5-commonjs5.types b/tests/baselines/reference/es5-commonjs5.types
new file mode 100644
index 0000000000000..d8094e1e0ea1b
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs5.types
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/es5-commonjs5.ts ===
+
+export default function () {
+	return "test";
+>"test" : string
+}
+
diff --git a/tests/baselines/reference/es5-commonjs6.js b/tests/baselines/reference/es5-commonjs6.js
new file mode 100644
index 0000000000000..7c2c8b21779d9
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs6.js
@@ -0,0 +1,10 @@
+//// [es5-commonjs6.ts]
+
+export default "test";
+var __esModule = 1;
+
+
+//// [es5-commonjs6.js]
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.default = "test";
+var __esModule = 1;
diff --git a/tests/baselines/reference/es5-commonjs6.symbols b/tests/baselines/reference/es5-commonjs6.symbols
new file mode 100644
index 0000000000000..7a2847e0f25e0
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs6.symbols
@@ -0,0 +1,6 @@
+=== tests/cases/compiler/es5-commonjs6.ts ===
+
+export default "test";
+var __esModule = 1;
+>__esModule : Symbol(__esModule, Decl(es5-commonjs6.ts, 2, 3))
+
diff --git a/tests/baselines/reference/es5-commonjs6.types b/tests/baselines/reference/es5-commonjs6.types
new file mode 100644
index 0000000000000..904b69dec2244
--- /dev/null
+++ b/tests/baselines/reference/es5-commonjs6.types
@@ -0,0 +1,7 @@
+=== tests/cases/compiler/es5-commonjs6.ts ===
+
+export default "test";
+var __esModule = 1;
+>__esModule : number
+>1 : number
+
diff --git a/tests/baselines/reference/es5-system.js b/tests/baselines/reference/es5-system.js
new file mode 100644
index 0000000000000..2674527722a9e
--- /dev/null
+++ b/tests/baselines/reference/es5-system.js
@@ -0,0 +1,34 @@
+//// [es5-system.ts]
+
+export default class A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+    {
+        return 42;
+    }
+}
+
+
+//// [es5-system.js]
+System.register([], function(exports_1) {
+    var A;
+    return {
+        setters:[],
+        execute: function() {
+            A = (function () {
+                function A() {
+                }
+                A.prototype.B = function () {
+                    return 42;
+                };
+                return A;
+            })();
+            exports_1("default", A);
+        }
+    }
+});
diff --git a/tests/baselines/reference/es5-system.symbols b/tests/baselines/reference/es5-system.symbols
new file mode 100644
index 0000000000000..5211e3c4259d5
--- /dev/null
+++ b/tests/baselines/reference/es5-system.symbols
@@ -0,0 +1,17 @@
+=== tests/cases/compiler/es5-system.ts ===
+
+export default class A
+>A : Symbol(A, Decl(es5-system.ts, 0, 0))
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+>B : Symbol(B, Decl(es5-system.ts, 6, 5))
+    {
+        return 42;
+    }
+}
+
diff --git a/tests/baselines/reference/es5-system.types b/tests/baselines/reference/es5-system.types
new file mode 100644
index 0000000000000..eae884a78b45d
--- /dev/null
+++ b/tests/baselines/reference/es5-system.types
@@ -0,0 +1,18 @@
+=== tests/cases/compiler/es5-system.ts ===
+
+export default class A
+>A : A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+>B : () => number
+    {
+        return 42;
+>42 : number
+    }
+}
+
diff --git a/tests/baselines/reference/es5-umd3.js b/tests/baselines/reference/es5-umd3.js
index 3abb92f816fb9..92ac306698a43 100644
--- a/tests/baselines/reference/es5-umd3.js
+++ b/tests/baselines/reference/es5-umd3.js
@@ -31,5 +31,6 @@ export default class A
         };
         return A;
     })();
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = A;
 });
diff --git a/tests/baselines/reference/es5ExportDefaultClassDeclaration.js b/tests/baselines/reference/es5ExportDefaultClassDeclaration.js
index b5cfdb02f7838..0d4076e39a183 100644
--- a/tests/baselines/reference/es5ExportDefaultClassDeclaration.js
+++ b/tests/baselines/reference/es5ExportDefaultClassDeclaration.js
@@ -12,6 +12,7 @@ var C = (function () {
     C.prototype.method = function () { };
     return C;
 })();
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = C;
 
 
diff --git a/tests/baselines/reference/es5ExportDefaultClassDeclaration2.js b/tests/baselines/reference/es5ExportDefaultClassDeclaration2.js
index de0d109dadf8d..5e5eeae1f0f93 100644
--- a/tests/baselines/reference/es5ExportDefaultClassDeclaration2.js
+++ b/tests/baselines/reference/es5ExportDefaultClassDeclaration2.js
@@ -12,6 +12,7 @@ var default_1 = (function () {
     default_1.prototype.method = function () { };
     return default_1;
 })();
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = default_1;
 
 
diff --git a/tests/baselines/reference/es5ExportDefaultClassDeclaration3.js b/tests/baselines/reference/es5ExportDefaultClassDeclaration3.js
index bff80940a02cb..a977447f9ad6d 100644
--- a/tests/baselines/reference/es5ExportDefaultClassDeclaration3.js
+++ b/tests/baselines/reference/es5ExportDefaultClassDeclaration3.js
@@ -24,6 +24,7 @@ var C = (function () {
     };
     return C;
 })();
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = C;
 var after = new C();
 var t = C;
diff --git a/tests/baselines/reference/es5ExportDefaultExpression.js b/tests/baselines/reference/es5ExportDefaultExpression.js
index 944b6fc71a5fc..a825e45971bb6 100644
--- a/tests/baselines/reference/es5ExportDefaultExpression.js
+++ b/tests/baselines/reference/es5ExportDefaultExpression.js
@@ -4,6 +4,7 @@ export default (1 + 2);
 
 
 //// [es5ExportDefaultExpression.js]
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = (1 + 2);
 
 
diff --git a/tests/baselines/reference/es5ExportDefaultFunctionDeclaration.js b/tests/baselines/reference/es5ExportDefaultFunctionDeclaration.js
index 673cc3cb4534b..afc44ac53f506 100644
--- a/tests/baselines/reference/es5ExportDefaultFunctionDeclaration.js
+++ b/tests/baselines/reference/es5ExportDefaultFunctionDeclaration.js
@@ -5,6 +5,7 @@ export default function f() { }
 
 //// [es5ExportDefaultFunctionDeclaration.js]
 function f() { }
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = f;
 
 
diff --git a/tests/baselines/reference/es5ExportDefaultFunctionDeclaration2.js b/tests/baselines/reference/es5ExportDefaultFunctionDeclaration2.js
index ad1334e810b6c..10f1db6a0eb1d 100644
--- a/tests/baselines/reference/es5ExportDefaultFunctionDeclaration2.js
+++ b/tests/baselines/reference/es5ExportDefaultFunctionDeclaration2.js
@@ -5,6 +5,7 @@ export default function () { }
 
 //// [es5ExportDefaultFunctionDeclaration2.js]
 function default_1() { }
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = default_1;
 
 
diff --git a/tests/baselines/reference/es5ExportDefaultFunctionDeclaration3.js b/tests/baselines/reference/es5ExportDefaultFunctionDeclaration3.js
index 1fc5797643948..af437c087662e 100644
--- a/tests/baselines/reference/es5ExportDefaultFunctionDeclaration3.js
+++ b/tests/baselines/reference/es5ExportDefaultFunctionDeclaration3.js
@@ -13,6 +13,7 @@ var before = func();
 function func() {
     return func;
 }
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = func;
 var after = func();
 
diff --git a/tests/baselines/reference/es5ExportDefaultIdentifier.js b/tests/baselines/reference/es5ExportDefaultIdentifier.js
index 739f3d6c1095e..c8fb6b3be2785 100644
--- a/tests/baselines/reference/es5ExportDefaultIdentifier.js
+++ b/tests/baselines/reference/es5ExportDefaultIdentifier.js
@@ -8,6 +8,7 @@ export default f;
 //// [es5ExportDefaultIdentifier.js]
 function f() { }
 exports.f = f;
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = f;
 
 
diff --git a/tests/baselines/reference/es6ImportDefaultBindingAmd.js b/tests/baselines/reference/es6ImportDefaultBindingAmd.js
index 70e4f7e2f57a1..9c8cbec9db5cc 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingAmd.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingAmd.js
@@ -14,6 +14,7 @@ import defaultBinding2 from "es6ImportDefaultBindingAmd_0"; // elide this import
 //// [es6ImportDefaultBindingAmd_0.js]
 define(["require", "exports"], function (require, exports) {
     var a = 10;
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = a;
 });
 //// [es6ImportDefaultBindingAmd_1.js]
diff --git a/tests/baselines/reference/es6ImportDefaultBindingDts.js b/tests/baselines/reference/es6ImportDefaultBindingDts.js
index caa46ed30efe2..a5e8d509da113 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingDts.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingDts.js
@@ -17,6 +17,7 @@ var c = (function () {
     }
     return c;
 })();
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = c;
 //// [client.js]
 var server_1 = require("server");
diff --git a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1InEs5.js b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1InEs5.js
index 15ca1284a1e0b..7090b7a066389 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1InEs5.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1InEs5.js
@@ -22,6 +22,7 @@ var x: number = defaultBinding6;
 
 //// [es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0.js]
 var a = 10;
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = a;
 //// [es6ImportDefaultBindingFollowedWithNamedImport1InEs5_1.js]
 var es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0_1 = require("es6ImportDefaultBindingFollowedWithNamedImport1InEs5_0");
diff --git a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1WithExport.js b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1WithExport.js
index b6b03176df115..2b0e3ebbeb520 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1WithExport.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImport1WithExport.js
@@ -22,6 +22,7 @@ export var x1: number = defaultBinding6;
 
 //// [server.js]
 var a = 10;
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = a;
 //// [client.js]
 var server_1 = require("server");
diff --git a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImportDts1.js b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImportDts1.js
index e6211ac1ebec0..dad034c618cab 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImportDts1.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImportDts1.js
@@ -25,6 +25,7 @@ var a = (function () {
     }
     return a;
 })();
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = a;
 //// [client.js]
 var server_1 = require("server");
diff --git a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImportWithExport.js b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImportWithExport.js
index 90521007735c0..b7da05d7dbbb9 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImportWithExport.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamedImportWithExport.js
@@ -27,6 +27,7 @@ define(["require", "exports"], function (require, exports) {
     exports.a = 10;
     exports.x = exports.a;
     exports.m = exports.a;
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = {};
 });
 //// [client.js]
diff --git a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBinding1InEs5.js b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBinding1InEs5.js
index c2bd5476a7c4e..4a9871102248f 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBinding1InEs5.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBinding1InEs5.js
@@ -11,6 +11,7 @@ var x: number = defaultBinding;
 
 //// [es6ImportDefaultBindingFollowedWithNamespaceBindingInEs5_0.js]
 var a = 10;
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = a;
 //// [es6ImportDefaultBindingFollowedWithNamespaceBindingInEs5_1.js]
 var es6ImportDefaultBindingFollowedWithNamespaceBindingInEs5_0_1 = require("es6ImportDefaultBindingFollowedWithNamespaceBindingInEs5_0"), nameSpaceBinding = es6ImportDefaultBindingFollowedWithNamespaceBindingInEs5_0_1;
diff --git a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBinding1WithExport.js b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBinding1WithExport.js
index ed40582e9231d..a032325fbb446 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBinding1WithExport.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBinding1WithExport.js
@@ -12,6 +12,7 @@ export var x: number = defaultBinding;
 //// [server.js]
 define(["require", "exports"], function (require, exports) {
     var a = 10;
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = a;
 });
 //// [client.js]
diff --git a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBindingDts1.js b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBindingDts1.js
index e03ded5fd5aaf..639ffce59fd0b 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBindingDts1.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingFollowedWithNamespaceBindingDts1.js
@@ -16,6 +16,7 @@ define(["require", "exports"], function (require, exports) {
         }
         return a;
     })();
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = a;
 });
 //// [client.js]
diff --git a/tests/baselines/reference/es6ImportDefaultBindingMergeErrors.js b/tests/baselines/reference/es6ImportDefaultBindingMergeErrors.js
index 1208ace5ddef4..10b8bec03c72f 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingMergeErrors.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingMergeErrors.js
@@ -18,6 +18,7 @@ import defaultBinding3 from "es6ImportDefaultBindingMergeErrors_0"; // SHould be
 
 //// [es6ImportDefaultBindingMergeErrors_0.js]
 var a = 10;
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = a;
 //// [es6ImportDefaultBindingMergeErrors_1.js]
 var es6ImportDefaultBindingMergeErrors_0_1 = require("es6ImportDefaultBindingMergeErrors_0");
diff --git a/tests/baselines/reference/es6ImportDefaultBindingWithExport.js b/tests/baselines/reference/es6ImportDefaultBindingWithExport.js
index e2c5fab4c94b6..2fb7f0644b9ca 100644
--- a/tests/baselines/reference/es6ImportDefaultBindingWithExport.js
+++ b/tests/baselines/reference/es6ImportDefaultBindingWithExport.js
@@ -13,6 +13,7 @@ export import defaultBinding2 from "server"; // non referenced
 //// [server.js]
 define(["require", "exports"], function (require, exports) {
     var a = 10;
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = a;
 });
 //// [client.js]
diff --git a/tests/baselines/reference/exportAndImport-es3-amd.js b/tests/baselines/reference/exportAndImport-es3-amd.js
index a4552e70d68d2..d2293a56e2365 100644
--- a/tests/baselines/reference/exportAndImport-es3-amd.js
+++ b/tests/baselines/reference/exportAndImport-es3-amd.js
@@ -16,6 +16,7 @@ export default function f2() {
 define(["require", "exports"], function (require, exports) {
     function f1() {
     }
+    exports.__esModule = true;
     exports["default"] = f1;
 });
 //// [m2.js]
@@ -23,5 +24,6 @@ define(["require", "exports", "./m1"], function (require, exports, m1_1) {
     function f2() {
         m1_1["default"]();
     }
+    exports.__esModule = true;
     exports["default"] = f2;
 });
diff --git a/tests/baselines/reference/exportAndImport-es3.js b/tests/baselines/reference/exportAndImport-es3.js
index 5f467509b689c..1be548bc9305c 100644
--- a/tests/baselines/reference/exportAndImport-es3.js
+++ b/tests/baselines/reference/exportAndImport-es3.js
@@ -15,10 +15,12 @@ export default function f2() {
 //// [m1.js]
 function f1() {
 }
+exports.__esModule = true;
 exports["default"] = f1;
 //// [m2.js]
 var m1_1 = require("./m1");
 function f2() {
     m1_1["default"]();
 }
+exports.__esModule = true;
 exports["default"] = f2;
diff --git a/tests/baselines/reference/exportAndImport-es5-amd.js b/tests/baselines/reference/exportAndImport-es5-amd.js
index 4966af874f7fa..447356b12302a 100644
--- a/tests/baselines/reference/exportAndImport-es5-amd.js
+++ b/tests/baselines/reference/exportAndImport-es5-amd.js
@@ -16,6 +16,7 @@ export default function f2() {
 define(["require", "exports"], function (require, exports) {
     function f1() {
     }
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = f1;
 });
 //// [m2.js]
@@ -23,5 +24,6 @@ define(["require", "exports", "./m1"], function (require, exports, m1_1) {
     function f2() {
         m1_1.default();
     }
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = f2;
 });
diff --git a/tests/baselines/reference/exportAndImport-es5.js b/tests/baselines/reference/exportAndImport-es5.js
index 02d0e43e5a91e..c0bacb94aeef0 100644
--- a/tests/baselines/reference/exportAndImport-es5.js
+++ b/tests/baselines/reference/exportAndImport-es5.js
@@ -15,10 +15,12 @@ export default function f2() {
 //// [m1.js]
 function f1() {
 }
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = f1;
 //// [m2.js]
 var m1_1 = require("./m1");
 function f2() {
     m1_1.default();
 }
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = f2;
diff --git a/tests/baselines/reference/exportStar-amd.js b/tests/baselines/reference/exportStar-amd.js
index dcd2d126a3539..534a23b4d5bd7 100644
--- a/tests/baselines/reference/exportStar-amd.js
+++ b/tests/baselines/reference/exportStar-amd.js
@@ -36,6 +36,7 @@ define(["require", "exports"], function (require, exports) {
 });
 //// [t2.js]
 define(["require", "exports"], function (require, exports) {
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = "hello";
     function foo() { }
     exports.foo = foo;
diff --git a/tests/baselines/reference/exportStar.js b/tests/baselines/reference/exportStar.js
index d219a3650e727..74cf24a0f9718 100644
--- a/tests/baselines/reference/exportStar.js
+++ b/tests/baselines/reference/exportStar.js
@@ -33,6 +33,7 @@ foo;
 exports.x = 1;
 exports.y = 2;
 //// [t2.js]
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = "hello";
 function foo() { }
 exports.foo = foo;
diff --git a/tests/baselines/reference/exportsAndImports4-amd.js b/tests/baselines/reference/exportsAndImports4-amd.js
index db28ed5b35009..e6a431854b27b 100644
--- a/tests/baselines/reference/exportsAndImports4-amd.js
+++ b/tests/baselines/reference/exportsAndImports4-amd.js
@@ -41,6 +41,7 @@ export { a, b, c, d, e1, e2, f1, f2 };
 
 //// [t1.js]
 define(["require", "exports"], function (require, exports) {
+    Object.defineProperty(exports, "__esModule", { value: true });
     exports.default = "hello";
 });
 //// [t3.js]
diff --git a/tests/baselines/reference/exportsAndImports4.js b/tests/baselines/reference/exportsAndImports4.js
index ea5f34b882be8..7358b31eacec3 100644
--- a/tests/baselines/reference/exportsAndImports4.js
+++ b/tests/baselines/reference/exportsAndImports4.js
@@ -40,6 +40,7 @@ export { a, b, c, d, e1, e2, f1, f2 };
 
 
 //// [t1.js]
+Object.defineProperty(exports, "__esModule", { value: true });
 exports.default = "hello";
 //// [t3.js]
 var a = require("./t1");
diff --git a/tests/baselines/reference/tsxAttributeResolution9.symbols b/tests/baselines/reference/tsxAttributeResolution9.symbols
deleted file mode 100644
index 081482d5d47a4..0000000000000
--- a/tests/baselines/reference/tsxAttributeResolution9.symbols
+++ /dev/null
@@ -1,47 +0,0 @@
-=== tests/cases/conformance/jsx/react.d.ts ===
-
-declare module JSX {
->JSX : Symbol(JSX, Decl(react.d.ts, 0, 0))
-
-	interface Element { }
->Element : Symbol(Element, Decl(react.d.ts, 1, 20))
-
-	interface IntrinsicElements {
->IntrinsicElements : Symbol(IntrinsicElements, Decl(react.d.ts, 2, 22))
-	}
-	interface ElementAttributesProperty {
->ElementAttributesProperty : Symbol(ElementAttributesProperty, Decl(react.d.ts, 4, 2))
-
-		props;
->props : Symbol(props, Decl(react.d.ts, 5, 38))
-	}
-}
-
-interface Props {  
->Props : Symbol(Props, Decl(react.d.ts, 8, 1))
-
-  foo: string;
->foo : Symbol(foo, Decl(react.d.ts, 10, 17))
-}
-
-=== tests/cases/conformance/jsx/file.tsx ===
-export class MyComponent {  
->MyComponent : Symbol(MyComponent, Decl(file.tsx, 0, 0))
-
-  render() {
->render : Symbol(render, Decl(file.tsx, 0, 26))
-  }
-
-  props: { foo: string; }
->props : Symbol(props, Decl(file.tsx, 2, 3))
->foo : Symbol(foo, Decl(file.tsx, 4, 10))
-}
-
-<MyComponent foo="bar" />; // ok  
->MyComponent : Symbol(MyComponent, Decl(file.tsx, 0, 0))
->foo : Symbol(unknown)
-
-<MyComponent foo={0} />; // should be an error
->MyComponent : Symbol(MyComponent, Decl(file.tsx, 0, 0))
->foo : Symbol(unknown)
-
diff --git a/tests/baselines/reference/tsxAttributeResolution9.types b/tests/baselines/reference/tsxAttributeResolution9.types
deleted file mode 100644
index 1b2c6d423896a..0000000000000
--- a/tests/baselines/reference/tsxAttributeResolution9.types
+++ /dev/null
@@ -1,49 +0,0 @@
-=== tests/cases/conformance/jsx/react.d.ts ===
-
-declare module JSX {
->JSX : any
-
-	interface Element { }
->Element : Element
-
-	interface IntrinsicElements {
->IntrinsicElements : IntrinsicElements
-	}
-	interface ElementAttributesProperty {
->ElementAttributesProperty : ElementAttributesProperty
-
-		props;
->props : any
-	}
-}
-
-interface Props {  
->Props : Props
-
-  foo: string;
->foo : string
-}
-
-=== tests/cases/conformance/jsx/file.tsx ===
-export class MyComponent {  
->MyComponent : MyComponent
-
-  render() {
->render : () => void
-  }
-
-  props: { foo: string; }
->props : { foo: string; }
->foo : string
-}
-
-<MyComponent foo="bar" />; // ok  
-><MyComponent foo="bar" /> : JSX.Element
->MyComponent : typeof MyComponent
->foo : any
-
-<MyComponent foo={0} />; // should be an error
-><MyComponent foo={0} /> : JSX.Element
->MyComponent : typeof MyComponent
->foo : any
-
diff --git a/tests/cases/compiler/es5-commonjs.ts b/tests/cases/compiler/es5-commonjs.ts
new file mode 100644
index 0000000000000..21eb3732ada08
--- /dev/null
+++ b/tests/cases/compiler/es5-commonjs.ts
@@ -0,0 +1,17 @@
+// @target: ES5
+// @sourcemap: false
+// @declaration: false
+// @module: commonjs
+
+export default class A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+    {
+        return 42;
+    }
+}
diff --git a/tests/cases/compiler/es5-commonjs2.ts b/tests/cases/compiler/es5-commonjs2.ts
new file mode 100644
index 0000000000000..c6b404c7ef5f2
--- /dev/null
+++ b/tests/cases/compiler/es5-commonjs2.ts
@@ -0,0 +1,6 @@
+// @target: ES5
+// @sourcemap: false
+// @declaration: false
+// @module: commonjs
+
+export default 1;
diff --git a/tests/cases/compiler/es5-commonjs3.ts b/tests/cases/compiler/es5-commonjs3.ts
new file mode 100644
index 0000000000000..54f2c9ac6fe1c
--- /dev/null
+++ b/tests/cases/compiler/es5-commonjs3.ts
@@ -0,0 +1,7 @@
+// @target: ES5
+// @sourcemap: false
+// @declaration: false
+// @module: commonjs
+
+export default "test";
+export var __esModule = 1;
diff --git a/tests/cases/compiler/es5-commonjs4.ts b/tests/cases/compiler/es5-commonjs4.ts
new file mode 100644
index 0000000000000..ce4f8ef68832d
--- /dev/null
+++ b/tests/cases/compiler/es5-commonjs4.ts
@@ -0,0 +1,18 @@
+// @target: ES5
+// @sourcemap: false
+// @declaration: false
+// @module: commonjs
+
+export default class A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+    {
+        return 42;
+    }
+}
+export var __esModule = 1;
diff --git a/tests/cases/compiler/es5-commonjs5.ts b/tests/cases/compiler/es5-commonjs5.ts
new file mode 100644
index 0000000000000..631dd11a39ae7
--- /dev/null
+++ b/tests/cases/compiler/es5-commonjs5.ts
@@ -0,0 +1,8 @@
+// @target: ES5
+// @sourcemap: false
+// @declaration: false
+// @module: commonjs
+
+export default function () {
+	return "test";
+}
diff --git a/tests/cases/compiler/es5-commonjs6.ts b/tests/cases/compiler/es5-commonjs6.ts
new file mode 100644
index 0000000000000..676e5bddb48ff
--- /dev/null
+++ b/tests/cases/compiler/es5-commonjs6.ts
@@ -0,0 +1,7 @@
+// @target: ES5
+// @sourcemap: false
+// @declaration: false
+// @module: commonjs
+
+export default "test";
+var __esModule = 1;
diff --git a/tests/cases/compiler/es5-system.ts b/tests/cases/compiler/es5-system.ts
new file mode 100644
index 0000000000000..e615f7e54121a
--- /dev/null
+++ b/tests/cases/compiler/es5-system.ts
@@ -0,0 +1,17 @@
+// @target: ES5
+// @sourcemap: false
+// @declaration: false
+// @module: system
+
+export default class A
+{
+    constructor ()
+    {
+
+    }
+
+    public B()
+    {
+        return 42;
+    }
+}