Support object literal shorthands

src/extra/ast.ts

@@ -446,9 +446,15 @@ export class ASTBuilder {
       for (let i = 1; i < numElements; ++i) {
         sb.push(",\n");
         indent(sb, this.indentLevel);
-        this.visitNode(names[i]);
-        sb.push(": ");
-        this.visitNode(values[i]);
+        let name = names[i];
+        let value = values[i];
+        if (name === value) {
+          this.visitNode(name);
+        } else {
+          this.visitNode(name);
+          sb.push(": ");
+          this.visitNode(value);
+        }
       }
       sb.push("\n");
       indent(sb, --this.indentLevel);

src/parser.ts

@@ -3093,17 +3093,20 @@ export class Parser extends DiagnosticEmitter {
           } else {
             name = Node.createIdentifierExpression(tn.readIdentifier(), tn.range());
           }
-          if (!tn.skip(Token.COLON)) {
+          names.push(name);
+          if (tn.skip(Token.COLON)) {
+            let value = this.parseExpression(tn, Precedence.COMMA + 1);
+            if (!value) return null;
+            values.push(value);
+          } else if (!name.is(CommonFlags.QUOTED)) {
+            values.push(name);
+          } else {
             this.error(
               DiagnosticCode._0_expected,
               tn.range(), ":"
             );
             return null;
           }
-          let value = this.parseExpression(tn, Precedence.COMMA + 1);
-          if (!value) return null;
-          names.push(name);
-          values.push(value);
           if (!tn.skip(Token.COMMA)) {
             if (tn.skip(Token.CLOSEBRACE)) {
               break;

tests/parser/object-literal.ts

@@ -4,6 +4,8 @@ var obj = {
   "c": false,
   d: {
     a: 123,
-    "b": {}
+    "b": {},
+    c,
+    d: d
   }
 };

tests/parser/object-literal.ts.fixture.ts

@@ -4,6 +4,8 @@ var obj = {
   "c": false,
   d: {
     a: 123,
-    "b": {}
+    "b": {},
+    c,
+    d: d
   }
 };