clang-format: [JS] handle destructuring `of`.

Summary:
Previously, clang-format would drop a space character between `of` and
then following (non-identifier) token if the preceding token was part of
a destructuring assignment (`}` or `]`).

Before:
    for (const [a, b] of[]) {}

After:
    for (const [a, b] of []) {}

Reviewers: djasper

Subscribers: klimek

Differential Revision: https://reviews.llvm.org/D40411

llvm-svn: 318942

2 files changed, 8 insertions, 2 deletions

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 3e102f8d3ca..0e2e8a8374d 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2397,9 +2397,11 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
     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).
+         // (e.g. as "const x of y" in a for loop), or after a destructuring
+         // operation (const [x, y] of z, const {a, b} of c).
          (Left.is(Keywords.kw_of) && Left.Previous &&
-          Left.Previous->Tok.getIdentifierInfo())) &&
+          (Left.Previous->Tok.getIdentifierInfo() ||
+           Left.Previous->isOneOf(tok::r_square, tok::r_brace)))) &&
         (!Left.Previous || !Left.Previous->is(tok::period)))
       return true;
     if (Left.isOneOf(tok::kw_for, Keywords.kw_as) && Left.Previous &&
diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index 3e5abdc098a..d9176599fb7 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -1110,6 +1110,10 @@ TEST_F(FormatTestJS, ForLoops) {
                "}");
   verifyFormat("for (let {a, b} of x) {\n"
                "}");
+  verifyFormat("for (let {a, b} of [x]) {\n"
+               "}");
+  verifyFormat("for (let [a, b] of [x]) {\n"
+               "}");
   verifyFormat("for (let {a, b} in x) {\n"
                "}");
 }