clang-format: [JS] fix whitespace around "of" operator.

[mprobst]

Summary

Previously:

import {of } from 'x';
of (null);

Now:

import {of} from 'x';
of(null);

[djasper]

lib/Format/TokenAnnotator.cpp

2275 ↗

(On Diff #94158)

Maybe:

// "of" is only a keyword if it appears after another identifier
// (e.g. as "const x of y" in a for loop).

[mprobst]

• improve comment

cfe/trunk/lib/Format/TokenAnnotator.cpp

if (Right.is(tok::star) &&
       return false;
     if (Right.isOneOf(tok::l_brace, tok::l_square) &&
         Left.isOneOf(Keywords.kw_function, Keywords.kw_yield))
       return true;
     // JS methods can use some keywords as names (e.g. `delete()`).
     if (Right.is(tok::l_paren) && Line.MustBeDeclaration &&
         Left.Tok.getIdentifierInfo())
       return false;
-    if (Left.isOneOf(Keywords.kw_let, Keywords.kw_var, Keywords.kw_in,
-                     Keywords.kw_of, tok::kw_const) &&
+    if ((Left.isOneOf(Keywords.kw_let, Keywords.kw_var, Keywords.kw_in,
+                      tok::kw_const) ||
+         // "of" is only a keyword if it appears after another identifier
+         // (e.g. as "const x of y" in a for loop).
+         (Left.is(Keywords.kw_of) && Left.Previous &&
+          Left.Previous->Tok.getIdentifierInfo())) &&
         (!Left.Previous || !Left.Previous->is(tok::period)))
       return true;
     if (Left.isOneOf(tok::kw_for, Keywords.kw_as) && Left.Previous &&
         Left.Previous->is(tok::period) && Right.is(tok::l_paren))
       return false;
     if (Left.is(Keywords.kw_as) &&
         Right.isOneOf(tok::l_square, tok::l_brace, tok::l_paren))
       return true;

cfe/trunk/unittests/Format/FormatTestJS.cpp

 TEST_F(FormatTestJS, ReservedWords) {
   // JavaScript reserved words (aka keywords) are only illegal when used as
   // Identifiers, but are legal as IdentifierNames.
   verifyFormat("x.class.struct = 1;");
   verifyFormat("x.case = 1;");
   verifyFormat("x.interface = 1;");
   verifyFormat("x.for = 1;");
   verifyFormat("x.of() = 1;");
+  verifyFormat("of(null);");
+  verifyFormat("import {of} from 'x';");
   verifyFormat("x.in() = 1;");
   verifyFormat("x.let() = 1;");
   verifyFormat("x.var() = 1;");
   verifyFormat("x.for() = 1;");
   verifyFormat("x.as() = 1;");
   verifyFormat("x = {\n"
                "  a: 12,\n"
                "  interface: 1,\n"