clang-format: [js] Support classes.

[mprobst]

Summary

This adds support for JavaScript class definitions (again following TypeScript & AtScript style). This only required support for visibility modifiers in JS, everything else was already working.

[djasper]

lib/Format/UnwrappedLineParser.cpp

833–835

As JavaScript also doesn't have function-like macros without trailing semicolon, could you move this to the outer if?

[djasper]

Submitted as r229701.

lib/Format/UnwrappedLineFormatter.h

private:
   typedef std::priority_queue<QueueItem, std::vector<QueueItem>,
                               std::greater<QueueItem> > QueueType;
 
   /// \brief Get the offset of the line relatively to the level.
   ///
   /// For example, 'public:' labels in classes are offset by 1 or 2
   /// characters to the left from their level.
   int getIndentOffset(const FormatToken &RootToken) {
-    if (Style.Language == FormatStyle::LK_Java)
+    if (Style.Language == FormatStyle::LK_Java ||
+        Style.Language == FormatStyle::LK_JavaScript)
       return 0;
     if (RootToken.isAccessSpecifier(false) || RootToken.isObjCAccessSpecifier())
       return Style.AccessModifierOffset;
     return 0;
   }
 
   /// \brief Add a new line and the required indent before the first Token
   /// of the \c UnwrappedLine if there was no structural parsing error.

lib/Format/UnwrappedLineParser.cpp

case tok::kw_inline:
     if (FormatTok->Tok.is(tok::kw_namespace)) {
       parseNamespace();
       return;
     }
     break;
   case tok::kw_public:
   case tok::kw_protected:
   case tok::kw_private:
-    if (Style.Language == FormatStyle::LK_Java)
+    if (Style.Language == FormatStyle::LK_Java ||
+        Style.Language == FormatStyle::LK_JavaScript)
       nextToken();
     else
       parseAccessSpecifier();
     return;
   case tok::kw_if:
     parseIfThenElse();
     return;
   case tok::kw_for:
case tok::identifier: {
       // Parse function literal unless 'function' is the first token in a line
       // in which case this should be treated as a free-standing function.
       if (Style.Language == FormatStyle::LK_JavaScript && Text == "function" &&
           Line->Tokens.size() > 0) {
         tryToParseJSFunction();
         break;
       }
       nextToken();
-      if (Line->Tokens.size() == 1) {
+      if (Line->Tokens.size() == 1 &&
+          // JS doesn't have macros, and within classes colons indicate fields,
+          // not labels.
+          (Style.Language != FormatStyle::LK_JavaScript ||
+           !Line->MustBeDeclaration)) {
         if (FormatTok->Tok.is(tok::colon)) {
           parseLabel();
           return;
         }
         // Recognize function-like macro usages without trailing semicolon as
-        // well as free-standing macrose like Q_OBJECT.
+        // well as free-standing macros like Q_OBJECT.
         bool FunctionLike = FormatTok->is(tok::l_paren);
         if (FunctionLike)
           parseParens();
         if (FormatTok->NewlinesBefore > 0 &&
             (Text.size() >= 5 || FunctionLike) &&
             tokenCanStartNewLine(FormatTok->Tok) && Text == Text.upper()) {
           addUnwrappedLine();
           return;

unittests/Format/FormatTestJS.cpp

TEST_F(FormatTestJS, TypeAnnotations) {
   verifyFormat("function x(): string {\n  return 'x';\n}");
   verifyFormat("function x(y: string): string {\n  return 'x';\n}");
   verifyFormat("for (var y: string in x) {\n  x();\n}");
   verifyFormat("((a: string, b: number): string => a + b);");
   verifyFormat("var x: (y: number) => string;");
   verifyFormat("var x: P<string, (a: number) => string>;");
 }
 
+TEST_F(FormatTestJS, ClassDeclarations) {
+  verifyFormat("class C {\n  x: string = 12;\n}");
+  verifyFormat("class C {\n  x(): string => 12;\n}");
+  verifyFormat("class C {\n  ['x' + 2]: string = 12;\n}");
+  verifyFormat("class C {\n  private x: string = 12;\n}");
+  verifyFormat("class C {\n  private static x: string = 12;\n}");
+  verifyFormat("class C {\n  static x(): string { return 'asd'; }\n}");
+  verifyFormat("class C extends P implements I {}");
+}
+
 } // end namespace tooling
 } // end namespace clang