clang-format: [JS] support cast syntax and type arguments.

[mprobst]

Summary

Casts in TS syntax (foo = <type>bar;) should not be followed by whitespace.

[djasper]

Please upload patch with full context in the future. Phabricator can't/doesn't access the existing repository to get the context.

lib/Format/TokenAnnotator.cpp

1760

So, there is a of spaceRequiredBefore and spaceRequiredBetween. It is entirely historic, not logical, essentially those two are just in sequence. However, I'd prefer to move this to spaceRequiredBefore, which has a JavaScript-specific section at the top.

[djasper]

Made the suggested change and submitted as r232321.

lib/Format/TokenAnnotator.cpp

     return false;
   if (Left.is(TT_TemplateCloser) && Right.is(tok::l_square))
     return false;
+  if (Left.is(TT_TemplateCloser) &&
+      Style.Language == FormatStyle::LK_JavaScript &&
+      !Right.isOneOf(tok::l_brace, tok::comma, tok::l_square,
+                     Keywords.kw_implements, Keywords.kw_extends))
+    // Type assertions ('<type>expr') are not followed by whitespace. Other
+    // locations that should have whitespace following are identified by the
+    // above set of follower tokens.
+    return false;
   return true;
 }
 

unittests/Format/FormatTestJS.cpp

   verifyFormat("var x = `hello` == `hello`;");
 }
 
+TEST_F(FormatTestJS, CastSyntax) {
+  verifyFormat("var x = <type>foo;");
+}
+
+TEST_F(FormatTestJS, TypeArguments) {
+  verifyFormat("class X<Y> {}");
+  verifyFormat("new X<Y>();");
+  verifyFormat("foo<Y>(a);");
+  verifyFormat("var x: X<Y>[];");
+  verifyFormat("class C extends D<E> implements F<G>, H<I> {}");
+}
+
 } // end namespace tooling
 } // end namespace clang