From a39a675696281d2edae5cc568296178ee3fb5fce Mon Sep 17 00:00:00 2001
From: Alexander T <alexander.tarasyuk@outlook.com>
Date: Mon, 23 Dec 2019 22:27:54 +0200
Subject: [PATCH] fix(35474): formatter incorrectly adds space after increment
 (#35550)

---
 src/services/formatting/rules.ts              |  2 +-
 .../spaceBeforeAndAfterBinaryOperators.ts     | 32 +++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 tests/cases/fourslash/spaceBeforeAndAfterBinaryOperators.ts

diff --git a/src/services/formatting/rules.ts b/src/services/formatting/rules.ts
index 59dcabfd6bc..d93ce595ae1 100644
--- a/src/services/formatting/rules.ts
+++ b/src/services/formatting/rules.ts
@@ -433,9 +433,9 @@ namespace ts.formatting {
     }
 
     function isBinaryOpContext(context: FormattingContext): boolean {
-
         switch (context.contextNode.kind) {
             case SyntaxKind.BinaryExpression:
+                return (<BinaryExpression>context.contextNode).operatorToken.kind !== SyntaxKind.CommaToken;
             case SyntaxKind.ConditionalExpression:
             case SyntaxKind.ConditionalType:
             case SyntaxKind.AsExpression:
diff --git a/tests/cases/fourslash/spaceBeforeAndAfterBinaryOperators.ts b/tests/cases/fourslash/spaceBeforeAndAfterBinaryOperators.ts
new file mode 100644
index 00000000000..6685de7bf9d
--- /dev/null
+++ b/tests/cases/fourslash/spaceBeforeAndAfterBinaryOperators.ts
@@ -0,0 +1,32 @@
+/// <reference path="fourslash.ts"/>
+
+////let i = 0;
+/////*1*/(i++,i++);
+/////*2*/(i++,++i);
+/////*3*/(1,2);
+/////*4*/(i++,2);
+/////*5*/(i++,i++,++i,i--,2);
+
+////let s = 'foo';
+/////*6*/for (var i = 0,ii = 2; i < s.length; ii++,i++) {
+////}
+
+format.document();
+
+goTo.marker("1");
+verify.currentLineContentIs(`(i++, i++);`);
+
+goTo.marker("2");
+verify.currentLineContentIs(`(i++, ++i);`);
+
+goTo.marker("3");
+verify.currentLineContentIs(`(1, 2);`);
+
+goTo.marker("4");
+verify.currentLineContentIs(`(i++, 2);`);
+
+goTo.marker("5");
+verify.currentLineContentIs(`(i++, i++, ++i, i--, 2);`);
+
+goTo.marker("6");
+verify.currentLineContentIs(`for (var i = 0, ii = 2; i < s.length; ii++, i++) {`);