clang-format: [JS] Handle keyword-named methods.

[mprobst]

Summary

Including do, for, and while, in addition to the previously
handled fields. The unit test explicitly uses methods, but this code
path handles both fields and methods.

[krasimir]

How about if and try? Is there a list somewhere for all such valid identifiers?

[MyDeveloperDay]

LGTM thanks for the patch

[mprobst]

In D72827#1823895, @krasimir wrote:

How about if and try? Is there a list somewhere for all such valid identifiers?

This is a bit annoying - generally speaking, we should parse all keywords in declaration locations as simple names. However UnwrappedLineParser isn't really structured to support that, nor is it precise enough to reliably detect these situations :-/ So I think the best we can do is incrementally detect these issues and fix as they come up.

[mprobst]

I've added tests and a fix for try/catch and if/else.

clang/lib/Format/UnwrappedLineParser.cpp

case tok::kw_private:
     else
       parseAccessSpecifier();
     return;
   case tok::kw_if:
     parseIfThenElse();
     return;
   case tok::kw_for:
   case tok::kw_while:
+    if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
+      // field/method declaration.
+      break;
     parseForOrWhileLoop();
     return;
   case tok::kw_do:
+    if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
+      // field/method declaration.
+      break;
     parseDoWhile();
     return;
   case tok::kw_switch:
     if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
       // 'switch: string' field declaration.
       break;
     parseSwitch();
     return;

clang/unittests/Format/FormatTestJS.cpp

verifyFormat("interface Test {\n"
                "  case: string;\n"
                "  default: string;\n"
                "}\n");
   verifyFormat("const Axis = {\n"
                "  for: 'for',\n"
                "  x: 'x'\n"
                "};",
                "const Axis = {for: 'for', x:   'x'};");
+  verifyFormat("class KeywordNamedMethods {\n"
+               "  do() {\n"
+               "  }\n"
+               "  for() {\n"
+               "  }\n"
+               "  while() {\n"
+               "  }\n"
+               "}\n");
 }
 
 TEST_F(FormatTestJS, ReservedWordsMethods) {
   verifyFormat(
       "class X {\n"
       "  delete() {\n"
       "    x();\n"
       "  }\n"