clang-format: [JS] exponentiation operator

[mprobst]

Summary

While its precedence should be higher than multiplicative, LLVM does not have a level for that, so for the time being just treat it as multiplicative.

[djasper]

unittests/Format/FormatTestJS.cpp

1791

Also make this handle **= ?

[mprobst]

• support **=

[djasper]

Thanks

lib/Format/FormatToken.h

#define LIST_TOKEN_TYPES \
   TYPE(FunctionTypeLParen) \
   TYPE(ImplicitStringLiteral) \
   TYPE(InheritanceColon) \
   TYPE(InheritanceComma) \
   TYPE(InlineASMBrace) \
   TYPE(InlineASMColon) \
   TYPE(JavaAnnotation) \
   TYPE(JsComputedPropertyName) \
+  TYPE(JsExponentiation) \
   TYPE(JsFatArrow) \
   TYPE(JsNonNullAssertion) \
   TYPE(JsTypeColon) \
   TYPE(JsTypeOperator) \
   TYPE(JsTypeOptionalQuestion) \
   TYPE(LambdaArrow) \
   TYPE(LambdaLSquare) \
   TYPE(LeadingJavaAnnotation) \

lib/Format/FormatTokenLexer.cpp

void FormatTokenLexer::tryMergePreviousTokens() {
 
   if (Style.Language == FormatStyle::LK_JavaScript) {
     static const tok::TokenKind JSIdentity[] = {tok::equalequal, tok::equal};
     static const tok::TokenKind JSNotIdentity[] = {tok::exclaimequal,
                                                    tok::equal};
     static const tok::TokenKind JSShiftEqual[] = {tok::greater, tok::greater,
                                                   tok::greaterequal};
     static const tok::TokenKind JSRightArrow[] = {tok::equal, tok::greater};
+    static const tok::TokenKind JSExponentiation[] = {tok::star, tok::star};
+
     // FIXME: Investigate what token type gives the correct operator priority.
     if (tryMergeTokens(JSIdentity, TT_BinaryOperator))
       return;
     if (tryMergeTokens(JSNotIdentity, TT_BinaryOperator))
       return;
     if (tryMergeTokens(JSShiftEqual, TT_BinaryOperator))
       return;
     if (tryMergeTokens(JSRightArrow, TT_JsFatArrow))
       return;
+    if (tryMergeTokens(JSExponentiation, TT_JsExponentiation))
+      return;
   }
 
   if (Style.Language == FormatStyle::LK_Java) {
     static const tok::TokenKind JavaRightLogicalShift[] = {tok::greater,
                                                            tok::greater,
                                                            tok::greater};
     static const tok::TokenKind JavaRightLogicalShiftAssign[] = {tok::greater,
                                                                  tok::greater,

unittests/Format/FormatTestJS.cpp

verifyFormat("class Foo {\n"
                "}");
 }
 
 TEST_F(FormatTestJS, ImportComments) {
   verifyFormat("import {x} from 'x';  // from some location",
                getGoogleJSStyleWithColumns(25));
   verifyFormat("// taze: x from 'location'", getGoogleJSStyleWithColumns(10));
 }
+
+TEST_F(FormatTestJS, Exponentiation) {
+  verifyFormat("squared = x ** 2;");
+}
+
 } // end namespace tooling
 } // end namespace clang