Inline decorators with no arguments (#1910)

Fixes #1898

src/printer.js

@@ -100,10 +100,11 @@ function genericPrint(path, options, printPath, args) {
         (decorator.type === "Identifier" ||
           decorator.type === "MemberExpression" ||
           (decorator.type === "CallExpression" &&
-            decorator.arguments.length === 1 &&
-            (isStringLiteral(decorator.arguments[0]) ||
-              decorator.arguments[0].type === "Identifier" ||
-              decorator.arguments[0].type === "MemberExpression")))
+            (decorator.arguments.length === 0 ||
+              (decorator.arguments.length === 1 &&
+                (isStringLiteral(decorator.arguments[0]) ||
+                  decorator.arguments[0].type === "Identifier" ||
+                  decorator.arguments[0].type === "MemberExpression")))))
       ) {
         separator = " ";
       }

tests/typescript_decorators/__snapshots__/jsfmt.spec.js.snap

@@ -11,6 +11,13 @@ export class TestTextFileService {
 @commonEditorContribution
 export class TabCompletionController {
 }
+
+@Component({
+  selector: 'angular-component',
+})
+class AngularComponent {
+  @Input() myInput: string;
+}
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 export class TestTextFileService {
   constructor(@ILifecycleService lifecycleService) {}
@@ -19,6 +26,13 @@ export class TestTextFileService {
 @commonEditorContribution
 export class TabCompletionController {}
 
+@Component({
+  selector: "angular-component"
+})
+class AngularComponent {
+  @Input() myInput: string;
+}
+
 `;
 
 exports[`inline-decorators.ts 1`] = `
@@ -95,8 +109,7 @@ class Class3 {
   @d1 fieldA;
   @d2(foo) fieldB;
   @d3.bar fieldC;
-  @d4.baz()
-  fieldD;
+  @d4.baz() fieldD;
 
   constructor(
     @d1 private x: number,

tests/typescript_decorators/decorators.js

@@ -8,3 +8,10 @@ export class TestTextFileService {
 @commonEditorContribution
 export class TabCompletionController {
 }
+
+@Component({
+  selector: 'angular-component',
+})
+class AngularComponent {
+  @Input() myInput: string;
+}