Empty switch should not have an empty line (#384)

Fixes #368

src/printer.js

@@ -971,10 +971,10 @@ function genericPrintNoParens(path, options, print) {
         "switch (",
         path.call(print, "discriminant"),
         ") {",
-        indent(
+        n.cases.length > 0 ? indent(
           options.tabWidth,
           concat([ hardline, join(hardline, path.map(print, "cases")) ])
-        ),
+        ) : "",
         hardline,
         "}"
       ]);

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

@@ -1,9 +1,12 @@
 exports[`test empty_switch.js 1`] = `
 "switch (1) { default:; }
+switch (1) {}
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 switch (1) {
   default:
 }
+switch (1) {
+}
 "
 `;
 

tests/switch/empty_switch.js

@@ -1 +1,2 @@
 switch (1) { default:; }
+switch (1) {}