JavaScript allows parameter lists to include trailing commas:

    myFunction(param1, param2,);

For symmetry with other parenthesized lists ([...], {...}), clang-format should
wrap parenthesized lists one-per-line if they contain a trailing comma:

    myFunction(
        param1,
        param2,
    );

This is particularly useful in function declarations or calls with many
arguments, e.g. commonly in constructors.

Differential Revision: https://reviews.llvm.org/D33023

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@303049 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 22 insertions, 6 deletions

diff --git a/lib/Format/ContinuationIndenter.cpp b/lib/Format/ContinuationIndenter.cpp
index 709eeb1539..488f9dd582 100644
--- a/lib/Format/ContinuationIndenter.cpp
+++ b/lib/Format/ContinuationIndenter.cpp
@@ -674,6 +674,8 @@ unsigned ContinuationIndenter::getNewLineColumn(const LineState &State) {
       return State.Stack[State.Stack.size() - 2].LastSpace;
     return State.FirstIndent;
   }
+  if (Current.is(tok::r_paren) && State.Stack.size() > 1)
+    return State.Stack[State.Stack.size() - 2].LastSpace;
   if (NextNonComment->is(TT_TemplateString) && NextNonComment->closesScope())
     return State.Stack[State.Stack.size() - 2].LastSpace;
   if (Current.is(tok::identifier) && Current.Next &&
@@ -1038,13 +1040,20 @@ void ContinuationIndenter::moveStatePastScopeOpener(LineState &State,
       NestedBlockIndent = Column;
     }
 
+    bool EndsInComma =
+        Current.MatchingParen &&
+        Current.MatchingParen->getPreviousNonComment() &&
+        Current.MatchingParen->getPreviousNonComment()->is(tok::comma);
+
     AvoidBinPacking =
+        (Style.Language == FormatStyle::LK_JavaScript && EndsInComma) ||
         (State.Line->MustBeDeclaration && !Style.BinPackParameters) ||
         (!State.Line->MustBeDeclaration && !Style.BinPackArguments) ||
         (Style.ExperimentalAutoDetectBinPacking &&
          (Current.PackingKind == PPK_OnePerLine ||
           (!BinPackInconclusiveFunctions &&
            Current.PackingKind == PPK_Inconclusive)));
+
     if (Current.is(TT_ObjCMethodExpr) && Current.MatchingParen) {
       if (Style.ColumnLimit) {
         // If this '[' opens an ObjC call, determine whether all parameters fit
@@ -1065,6 +1074,9 @@ void ContinuationIndenter::moveStatePastScopeOpener(LineState &State,
         }
       }
     }
+
+    if (Style.Language == FormatStyle::LK_JavaScript && EndsInComma)
+      BreakBeforeParameter = true;
   }
   // Generally inherit NoLineBreak from the current scope to nested scope.
   // However, don't do this for non-empty nested blocks, dict literals and
diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index bd5e2ed2f4..ad2166cfd3 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -2463,16 +2463,20 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
       return true;
   }
 
-  // If the last token before a '}' is a comma or a trailing comment, the
-  // intention is to insert a line break after it in order to make shuffling
-  // around entries easier.
+  // If the last token before a '}', ']', or ')' is a comma or a trailing
+  // comment, the intention is to insert a line break after it in order to make
+  // shuffling around entries easier.
   const FormatToken *BeforeClosingBrace = nullptr;
-  if (Left.isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) &&
+  if ((Left.isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) ||
+       (Style.Language == FormatStyle::LK_JavaScript &&
+        Left.is(tok::l_paren))) &&
       Left.BlockKind != BK_Block && Left.MatchingParen)
     BeforeClosingBrace = Left.MatchingParen->Previous;
   else if (Right.MatchingParen &&
-           Right.MatchingParen->isOneOf(tok::l_brace,
-                                        TT_ArrayInitializerLSquare))
+           (Right.MatchingParen->isOneOf(tok::l_brace,
+                                         TT_ArrayInitializerLSquare) ||
+            (Style.Language == FormatStyle::LK_JavaScript &&
+             Right.MatchingParen->is(tok::l_paren))))
     BeforeClosingBrace = &Left;
   if (BeforeClosingBrace && (BeforeClosingBrace->is(tok::comma) ||
                              BeforeClosingBrace->isTrailingComment()))