do not emit '=' in jsx attribute if initializer is missing

src/compiler/emitter.ts

@@ -1292,8 +1292,10 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, Promi
             function jsxEmitPreserve(node: JsxElement|JsxSelfClosingElement) {
                 function emitJsxAttribute(node: JsxAttribute) {
                     emit(node.name);
-                    write("=");
-                    emit(node.initializer);
+                    if (node.initializer) {
+                        write("=");
+                        emit(node.initializer);
+                    }
                 }
 
                 function emitJsxSpreadAttribute(node: JsxSpreadAttribute) {

tests/baselines/reference/jsxEmitAttributeWithPreserve.js

@@ -0,0 +1,7 @@
+//// [jsxEmitAttributeWithPreserve.tsx]
+
+declare var React: any;
+<foo data/>
+
+//// [jsxEmitAttributeWithPreserve.jsx]
+<foo data/>;

tests/baselines/reference/jsxEmitAttributeWithPreserve.symbols

@@ -0,0 +1,8 @@
+=== tests/cases/compiler/jsxEmitAttributeWithPreserve.tsx ===
+
+declare var React: any;
+>React : Symbol(React, Decl(jsxEmitAttributeWithPreserve.tsx, 1, 11))
+
+<foo data/>
+>data : Symbol(unknown)
+

tests/baselines/reference/jsxEmitAttributeWithPreserve.types

@@ -0,0 +1,10 @@
+=== tests/cases/compiler/jsxEmitAttributeWithPreserve.tsx ===
+
+declare var React: any;
+>React : any
+
+<foo data/>
+><foo data/> : any
+>foo : any
+>data : any
+

tests/baselines/reference/jsxInvalidEsprimaTestSuite.js

@@ -47,9 +47,9 @@ a /  > ;
     < a;
 b > ;
 b > ;
-<a b= c=></a>;
+<a b c></a>;
 b.c > ;
-<a.b c=></a.b>;
+<a.b c></a.b>;
 c > ;
 <a.b.c></a>;
     < .a > ;
@@ -67,7 +67,7 @@ var x = <div>one</div><div>two</div>;;
 var x = <div>one</div> /* intervening comment */ /* intervening comment */ <div>two</div>;;
 <a>{"str"}}</a>;
 <span className="a"/> id="b" />;
-<div className=/>>;
+<div className/>>;
 <div {...props}/>;
 
 <div>stuff</div>...props}>;

tests/baselines/reference/jsxReactTestSuite.js

@@ -158,14 +158,14 @@ var x = <div attr1={"foo" + "bar"} attr2={"foo" + "bar" +
 <Component constructor="foo"/>;
 <Namespace.Component />;
 <Namespace.DeepNamespace.Component />;
-<Component {...x} y={2} z=/>;
+<Component {...x} y={2} z/>;
 <Component {...this.props} sound="moo"/>;
 <font-face />;
 <Component x={y}/>;
 <x-component />;
 <Component {...x}/>;
 <Component {...x} y={2}/>;
-<Component {...x} y={2} z=/>;
+<Component {...x} y={2} z/>;
 <Component x={1} {...y}/>;
 <Component x={1} y="2" {...z} {...z}><Child /></Component>;
 <Component x="1" {...(z = { y: 2 }, z)} z={3}>Text</Component>;

tests/baselines/reference/tsxAttributeResolution6.js

@@ -20,10 +20,10 @@ declare module JSX {
 
 //// [tsxAttributeResolution6.jsx]
 // Error
-<test1 s=/>;
+<test1 s/>;
 <test1 n='true'/>;
 <test2 />;
 // OK
-<test1 n=/>;
+<test1 n/>;
 <test1 n={false}/>;
-<test2 n=/>;
+<test2 n/>;

tests/baselines/reference/tsxGenericArrowFunctionParsing.js

@@ -42,5 +42,5 @@ x3();
 var x4 = <T extends={true}>() => </T>;
 x4.isElement;
 // This is an element
-var x5 = <T extends=>() => </T>;
+var x5 = <T extends>() => </T>;
 x5.isElement;

tests/cases/compiler/jsxEmitAttributeWithPreserve.tsx

@@ -0,0 +1,4 @@
+//@jsx: preserve
+
+declare var React: any;
+<foo data/>