Do not put \n inside of empty object method bodies (#706)

Fixes #703

src/printer.js

@@ -542,7 +542,9 @@ function genericPrintNoParens(path, options, print) {
           !n.comments &&
           (parent.type === "ArrowFunctionExpression" ||
             parent.type === "FunctionExpression" ||
-            parent.type === "FunctionDeclaration")
+            parent.type === "FunctionDeclaration" ||
+            parent.type === "ObjectMethod" ||
+            parent.type === "ClassMethod")
       ) {
         return "{}";
       }

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

@@ -41,6 +41,10 @@ class A { // comment
 
 class A {
 }
+
+class A {
+  m() {}
+}
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 class A {
   // comment
@@ -51,6 +55,10 @@ class A {
 }
 
 class A {}
+
+class A {
+  m() {}
+}
 "
 `;
 

tests/classes/empty.js

@@ -7,3 +7,7 @@ class A { // comment
 
 class A {
 }
+
+class A {
+  m() {}
+}

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

@@ -9,6 +9,13 @@ a = () => ({}).x;
 "
 `;
 
+exports[`test method.js 1`] = `
+"a = { f() {} }
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+a = { f() {} };
+"
+`;
+
 exports[`test range.js 1`] = `
 "group(
   concat([

tests/objects/method.js

@@ -0,0 +1 @@
+a = { f() {} }