clang-format: [JS] do not collapse short classes.

Summary:
clang-format does not collapse short records, interfaces, unions, etc.,
but fails to do so if the record is preceded by certain modifiers
(export, default, abstract, declare). This change skips over all
modifiers, and thus handles all record definitions uniformly.

Before:
    export class Foo { bar: string; }
    class Baz {
      bam: string;
    }

After:
    export class Foo {
      bar: string;
    }
    class Baz {
      bam: string;
    }

Reviewers: djasper

Subscribers: klimek

Differential Revision: https://reviews.llvm.org/D40430

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@318976 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/UnwrappedLineFormatter.cpp

@@ -517,8 +517,13 @@ private:
       } else if (Limit != 0 && !Line.startsWith(tok::kw_namespace) &&
                  !startsExternCBlock(Line)) {
         // We don't merge short records.
-        FormatToken *RecordTok =
-            Line.First->is(tok::kw_typedef) ? Line.First->Next : Line.First;
+        FormatToken *RecordTok = Line.First;
+        // Skip record modifiers.
+        while (RecordTok->Next &&
+               RecordTok->isOneOf(tok::kw_typedef, tok::kw_export,
+                                  Keywords.kw_declare, Keywords.kw_abstract,
+                                  tok::kw_default))
+          RecordTok = RecordTok->Next;
         if (RecordTok &&
             RecordTok->isOneOf(tok::kw_class, tok::kw_union, tok::kw_struct,
                                Keywords.kw_interface))

unittests/Format/FormatTestJS.cpp

@@ -1674,9 +1674,15 @@ TEST_F(FormatTestJS, Modules) {
                "  x: number;\n"
                "  y: string;\n"
                "}");
-  verifyFormat("export class X { y: number; }");
-  verifyFormat("export abstract class X { y: number; }");
-  verifyFormat("export default class X { y: number }");
+  verifyFormat("export class X {\n"
+               "  y: number;\n"
+               "}");
+  verifyFormat("export abstract class X {\n"
+               "  y: number;\n"
+               "}");
+  verifyFormat("export default class X {\n"
+               "  y: number\n"
+               "}");
   verifyFormat("export default function() {\n  return 1;\n}");
   verifyFormat("export var x = 12;");
   verifyFormat("class C {}\n"
@@ -1698,7 +1704,9 @@ TEST_F(FormatTestJS, Modules) {
                "];");
   verifyFormat("export default [];");
   verifyFormat("export default () => {};");
-  verifyFormat("export interface Foo { foo: number; }\n"
+  verifyFormat("export interface Foo {\n"
+               "  foo: number;\n"
+               "}\n"
                "export class Bar {\n"
                "  blah(): string {\n"
                "    return this.blah;\n"