Index: cfe/trunk/lib/Format/TokenAnnotator.cpp
===================================================================
--- cfe/trunk/lib/Format/TokenAnnotator.cpp
+++ cfe/trunk/lib/Format/TokenAnnotator.cpp
@@ -2367,13 +2367,20 @@
         Left.isOneOf(Keywords.kw_function, Keywords.kw_yield,
                      Keywords.kw_extends, Keywords.kw_implements))
       return true;
-    // JS methods can use some keywords as names (e.g. `delete()`).
-    if (Right.is(tok::l_paren) && Line.MustBeDeclaration &&
-        Left.Tok.getIdentifierInfo())
-      return false;
-    if (Right.is(tok::l_paren) &&
-        Left.isOneOf(tok::kw_throw, Keywords.kw_await, Keywords.kw_typeof, tok::kw_void))
-      return true;
+    if (Right.is(tok::l_paren)) {
+      // JS methods can use some keywords as names (e.g. `delete()`).
+      if (Line.MustBeDeclaration && Left.Tok.getIdentifierInfo())
+        return false;
+      // Valid JS method names can include keywords, e.g. `foo.delete()` or
+      // `bar.instanceof()`. Recognize call positions by preceding period.
+      if (Left.Previous && Left.Previous->is(tok::period) &&
+          Left.Tok.getIdentifierInfo())
+        return false;
+      // Additional unary JavaScript operators that need a space after.
+      if (Left.isOneOf(tok::kw_throw, Keywords.kw_await, Keywords.kw_typeof,
+                       tok::kw_void))
+        return true;
+    }
     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
Index: cfe/trunk/unittests/Format/FormatTestJS.cpp
===================================================================
--- cfe/trunk/unittests/Format/FormatTestJS.cpp
+++ cfe/trunk/unittests/Format/FormatTestJS.cpp
@@ -271,14 +271,21 @@
   verifyFormat("x.case = 1;");
   verifyFormat("x.interface = 1;");
   verifyFormat("x.for = 1;");
-  verifyFormat("x.of() = 1;");
+  verifyFormat("x.of();");
   verifyFormat("of(null);");
   verifyFormat("import {of} from 'x';");
-  verifyFormat("x.in() = 1;");
-  verifyFormat("x.let() = 1;");
-  verifyFormat("x.var() = 1;");
-  verifyFormat("x.for() = 1;");
-  verifyFormat("x.as() = 1;");
+  verifyFormat("x.in();");
+  verifyFormat("x.let();");
+  verifyFormat("x.var();");
+  verifyFormat("x.for();");
+  verifyFormat("x.as();");
+  verifyFormat("x.instanceof();");
+  verifyFormat("x.switch();");
+  verifyFormat("x.case();");
+  verifyFormat("x.delete();");
+  verifyFormat("x.throw();");
+  verifyFormat("x.throws();");
+  verifyFormat("x.if();");
   verifyFormat("x = {\n"
                "  a: 12,\n"
                "  interface: 1,\n"
@@ -1228,7 +1235,6 @@
   // But, of course, "catch" is a perfectly fine function name in JavaScript.
   verifyFormat("someObject.catch();");
   verifyFormat("someObject.new();");
-  verifyFormat("someObject.delete();");
 }
 
 TEST_F(FormatTestJS, StringLiteralConcatenation) {