diff --git a/lib/Format/UnwrappedLineParser.cpp b/lib/Format/UnwrappedLineParser.cpp
index 32853dc209e68fc13a415176b1464bc5db7b3e3e..e6afd1f9887f5f6a24e85a2610a1937dfff25271 100644
--- a/lib/Format/UnwrappedLineParser.cpp
+++ b/lib/Format/UnwrappedLineParser.cpp
@@ -326,6 +326,11 @@ void UnwrappedLineParser::parseLevel(bool HasOpeningBrace) {
       break;
     case tok::kw_default:
     case tok::kw_case:
+      if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration) {
+        // A 'case: string' style field declaration.
+        parseStructuralElement();
+        break;
+      }
       if (!SwitchLabelEncountered &&
           (Style.IndentCaseLabels || (Line->InPPDirective && Line->Level == 1)))
         ++Line->Level;
@@ -953,13 +958,22 @@ void UnwrappedLineParser::parseStructuralElement() {
     parseDoWhile();
     return;
   case tok::kw_switch:
+    if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
+      // 'switch: string' field declaration.
+      break;
     parseSwitch();
     return;
   case tok::kw_default:
+    if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
+      // 'default: string' field declaration.
+      break;
     nextToken();
     parseLabel();
     return;
   case tok::kw_case:
+    if (Style.Language == FormatStyle::LK_JavaScript && Line->MustBeDeclaration)
+      // 'case: string' field declaration.
+      break;
     parseCaseLabel();
     return;
   case tok::kw_try:
diff --git a/unittests/Format/FormatTestJS.cpp b/unittests/Format/FormatTestJS.cpp
index 06f096a1d62d44e149e5c31bcd0c8466122a7020..67004f223fe7f33fb245d4f9e529d81b1f98f57c 100644
--- a/unittests/Format/FormatTestJS.cpp
+++ b/unittests/Format/FormatTestJS.cpp
@@ -242,6 +242,12 @@ TEST_F(FormatTestJS, ReservedWords) {
   verifyFormat("var interface = 2;");
   verifyFormat("interface = 2;");
   verifyFormat("x = interface instanceof y;");
+  verifyFormat("interface Test {\n"
+               "  x: string;\n"
+               "  switch: string;\n"
+               "  case: string;\n"
+               "  default: string;\n"
+               "}\n");
 }
 
 TEST_F(FormatTestJS, ReservedWordsMethods) {