clang-format: [JS] recognize exported type definitions.

[mprobst]

Summary

Support "export type T = {...};", in addition to just "type T = {...};".

[klimek]

lib/Format/TokenAnnotator.cpp

985–986

Change comment to "or export type X ="?

unittests/Format/FormatTestJS.cpp

1232

I see 2 changes to ifs but only one new test?

[mprobst]

• add comment

[mprobst]

unittests/Format/FormatTestJS.cpp

1232

The one test needs both conditions to succeed.

[klimek]

lg

lib/Format/TokenAnnotator.cpp

if (CurrentToken->is(tok::caret)) {
           MaybeSel->Previous->is(tok::at)) {
         StartsObjCMethodExpr = true;
       }
     }
 
     if (Left->is(TT_OverloadedOperatorLParen)) {
       Contexts.back().IsExpression = false;
     } else if (Style.Language == FormatStyle::LK_JavaScript &&
-               Line.startsWith(Keywords.kw_type, tok::identifier)) {
+               (Line.startsWith(Keywords.kw_type, tok::identifier) ||
+                Line.startsWith(tok::kw_export, Keywords.kw_type,
+                                tok::identifier))) {
       // type X = (...);
+      // export type X = (...);
       Contexts.back().IsExpression = false;
     } else if (Left->Previous &&
         (Left->Previous->isOneOf(tok::kw_static_assert, tok::kw_decltype,
                                  tok::kw_if, tok::kw_while, tok::l_paren,
                                  tok::comma) ||
          Left->Previous->is(TT_BinaryOperator))) {
       // static_assert, if and while usually contain expressions.
       Contexts.back().IsExpression = true;
struct ScopedContextCreator {
     }
 
     ~ScopedContextCreator() { P.Contexts.pop_back(); }
   };
 
   void modifyContext(const FormatToken &Current) {
     if (Current.getPrecedence() == prec::Assignment &&
         !Line.First->isOneOf(tok::kw_template, tok::kw_using, tok::kw_return) &&
-        // Type aliases use `type X = ...;` in TypeScript.
+        // Type aliases use `type X = ...;` in TypeScript and can be exported
+        // using `export type ...`.
         !(Style.Language == FormatStyle::LK_JavaScript &&
-          Line.startsWith(Keywords.kw_type, tok::identifier)) &&
+          (Line.startsWith(Keywords.kw_type, tok::identifier) ||
+           Line.startsWith(tok::kw_export, Keywords.kw_type,
+                           tok::identifier))) &&
         (!Current.Previous || Current.Previous->isNot(tok::kw_operator))) {
       Contexts.back().IsExpression = true;
       if (!Line.startsWith(TT_UnaryOperator)) {
         for (FormatToken *Previous = Current.Previous;
              Previous && Previous->Previous &&
              !Previous->Previous->isOneOf(tok::comma, tok::semi);
              Previous = Previous->Previous) {
           if (Previous->isOneOf(tok::r_square, tok::r_paren)) {

unittests/Format/FormatTestJS.cpp

TEST_F(FormatTestJS, UnionIntersectionTypes) {
   verifyFormat("function x(path: number|string) {}");
   verifyFormat("function x(): string|number {}");
   verifyFormat("type Foo = Bar|Baz;");
   verifyFormat("type Foo = Bar<X>|Baz;");
   verifyFormat("type Foo = (Bar<X>|Baz);");
   verifyFormat("let x: Bar|Baz;");
   verifyFormat("let x: Bar<X>|Baz;");
   verifyFormat("let x: (Foo|Bar)[];");
+  verifyFormat("type X = {\n"
+               "  a: Foo|Bar;\n"
+               "};");
+  verifyFormat("export type X = {\n"
+               "  a: Foo|Bar;\n"
+               "};");
 }
 
 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"
                "  foo() {}\n"