diff --git a/tests/baselines/reference/reactNamespaceJSXEmit.js b/tests/baselines/reference/reactNamespaceJSXEmit.js
index 26967d56b7b..fca5c611bbd 100644
--- a/tests/baselines/reference/reactNamespaceJSXEmit.js
+++ b/tests/baselines/reference/reactNamespaceJSXEmit.js
@@ -13,8 +13,15 @@ declare var x: any;
 
 
 //// [reactNamespaceJSXEmit.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var i = 1, n = arguments.length; i < n; i++) {
+        var s = arguments[i];
+        if (s != null) for (var p in s) if (s.hasOwnProperty(p)) t[p] = s[p];
+    }
+    return t;
+};
 myReactLib.createElement("foo", {data: true});
 myReactLib.createElement(Bar, {x: x});
 myReactLib.createElement("x-component", null);
-myReactLib.createElement(Bar, myReactLib.__spread({}, x));
-myReactLib.createElement(Bar, myReactLib.__spread({}, x, {y: 2}));
+myReactLib.createElement(Bar, __assign({}, x));
+myReactLib.createElement(Bar, __assign({}, x, {y: 2}));
diff --git a/tests/baselines/reference/tsxExternalModuleEmit2.js b/tests/baselines/reference/tsxExternalModuleEmit2.js
index 2233c5181cb..fcb41f7ce38 100644
--- a/tests/baselines/reference/tsxExternalModuleEmit2.js
+++ b/tests/baselines/reference/tsxExternalModuleEmit2.js
@@ -19,8 +19,15 @@ declare var Foo, React;
 
 //// [app.js]
 "use strict";
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var i = 1, n = arguments.length; i < n; i++) {
+        var s = arguments[i];
+        if (s != null) for (var p in s) if (s.hasOwnProperty(p)) t[p] = s[p];
+    }
+    return t;
+};
 var mod_1 = require('mod');
 // Should see mod_1['default'] in emit here
 React.createElement(Foo, {handler: mod_1["default"]});
 // Should see mod_1['default'] in emit here
-React.createElement(Foo, React.__spread({}, mod_1["default"]));
+React.createElement(Foo, __assign({}, mod_1["default"]));
diff --git a/tests/baselines/reference/tsxReactEmit2.js b/tests/baselines/reference/tsxReactEmit2.js
index fd7fff16976..cd086062a3c 100644
--- a/tests/baselines/reference/tsxReactEmit2.js
+++ b/tests/baselines/reference/tsxReactEmit2.js
@@ -16,9 +16,16 @@ var spreads5 = <div x={p2} {...p1} y={p3}>{p2}</div>;
 
 
 //// [file.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var i = 1, n = arguments.length; i < n; i++) {
+        var s = arguments[i];
+        if (s != null) for (var p in s) if (s.hasOwnProperty(p)) t[p] = s[p];
+    }
+    return t;
+};
 var p1, p2, p3;
-var spreads1 = React.createElement("div", React.__spread({}, p1), p2);
-var spreads2 = React.createElement("div", React.__spread({}, p1), p2);
-var spreads3 = React.createElement("div", React.__spread({x: p3}, p1), p2);
-var spreads4 = React.createElement("div", React.__spread({}, p1, {x: p3}), p2);
-var spreads5 = React.createElement("div", React.__spread({x: p2}, p1, {y: p3}), p2);
+var spreads1 = React.createElement("div", __assign({}, p1), p2);
+var spreads2 = React.createElement("div", __assign({}, p1), p2);
+var spreads3 = React.createElement("div", __assign({x: p3}, p1), p2);
+var spreads4 = React.createElement("div", __assign({}, p1, {x: p3}), p2);
+var spreads5 = React.createElement("div", __assign({x: p2}, p1, {y: p3}), p2);
diff --git a/tests/baselines/reference/tsxReactEmit4.js b/tests/baselines/reference/tsxReactEmit4.js
index d61cea24d2c..77350e54750 100644
--- a/tests/baselines/reference/tsxReactEmit4.js
+++ b/tests/baselines/reference/tsxReactEmit4.js
@@ -18,7 +18,14 @@ var openClosed1 = <div>
 var spread1 = <div {...p} x={0} />;
 
 //// [file.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var i = 1, n = arguments.length; i < n; i++) {
+        var s = arguments[i];
+        if (s != null) for (var p in s) if (s.hasOwnProperty(p)) t[p] = s[p];
+    }
+    return t;
+};
 var p;
 var openClosed1 = React.createElement("div", null, blah);
 // Should emit React.__spread({}, p, {x: 0})
-var spread1 = React.createElement("div", React.__spread({}, p, {x: 0}));
+var spread1 = React.createElement("div", __assign({}, p, {x: 0}));
diff --git a/tests/baselines/reference/tsxReactEmit5.js b/tests/baselines/reference/tsxReactEmit5.js
index 06b05f67d63..f4176aca387 100644
--- a/tests/baselines/reference/tsxReactEmit5.js
+++ b/tests/baselines/reference/tsxReactEmit5.js
@@ -23,8 +23,15 @@ var spread1 = <div x='' {...foo} y='' />;
 //// [file.js]
 //// [react-consumer.js]
 "use strict";
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var i = 1, n = arguments.length; i < n; i++) {
+        var s = arguments[i];
+        if (s != null) for (var p in s) if (s.hasOwnProperty(p)) t[p] = s[p];
+    }
+    return t;
+};
 var test_1 = require("./test");
 // Should emit test_1.React.createElement
 //  and React.__spread
 var foo;
-var spread1 = test_1.React.createElement("div", test_1.React.__spread({x: ''}, foo, {y: ''}));
+var spread1 = test_1.React.createElement("div", __assign({x: ''}, foo, {y: ''}));
diff --git a/tests/baselines/reference/tsxReactEmit6.js b/tests/baselines/reference/tsxReactEmit6.js
index 4f583929004..314f1936774 100644
--- a/tests/baselines/reference/tsxReactEmit6.js
+++ b/tests/baselines/reference/tsxReactEmit6.js
@@ -28,6 +28,13 @@ namespace M {
 
 //// [file.js]
 //// [react-consumer.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+    for (var i = 1, n = arguments.length; i < n; i++) {
+        var s = arguments[i];
+        if (s != null) for (var p in s) if (s.hasOwnProperty(p)) t[p] = s[p];
+    }
+    return t;
+};
 var M;
 (function (M) {
 })(M || (M = {}));
@@ -36,7 +43,7 @@ var M;
     // Should emit M.React.createElement
     //  and M.React.__spread
     var foo;
-    var spread1 = M.React.createElement("div", M.React.__spread({x: ''}, foo, {y: ''}));
+    var spread1 = M.React.createElement("div", __assign({x: ''}, foo, {y: ''}));
     // Quotes
     var x = M.React.createElement("div", null, "This \"quote\" thing");
 })(M || (M = {}));