Index: cfe/trunk/lib/Format/FormatToken.h
===================================================================
--- cfe/trunk/lib/Format/FormatToken.h
+++ cfe/trunk/lib/Format/FormatToken.h
@@ -53,6 +53,8 @@
   TYPE(InlineASMColon) \
   TYPE(JavaAnnotation) \
   TYPE(JsComputedPropertyName) \
+  TYPE(JsExponentiation) \
+  TYPE(JsExponentiationEqual) \
   TYPE(JsFatArrow) \
   TYPE(JsNonNullAssertion) \
   TYPE(JsTypeColon) \
Index: cfe/trunk/lib/Format/FormatTokenLexer.cpp
===================================================================
--- cfe/trunk/lib/Format/FormatTokenLexer.cpp
+++ cfe/trunk/lib/Format/FormatTokenLexer.cpp
@@ -74,6 +74,10 @@
     static const tok::TokenKind JSShiftEqual[] = {tok::greater, tok::greater,
                                                   tok::greaterequal};
     static const tok::TokenKind JSRightArrow[] = {tok::equal, tok::greater};
+    static const tok::TokenKind JSExponentiation[] = {tok::star, tok::star};
+    static const tok::TokenKind JSExponentiationEqual[] = {tok::star,
+                                                           tok::starequal};
+
     // FIXME: Investigate what token type gives the correct operator priority.
     if (tryMergeTokens(JSIdentity, TT_BinaryOperator))
       return;
@@ -83,6 +87,12 @@
       return;
     if (tryMergeTokens(JSRightArrow, TT_JsFatArrow))
       return;
+    if (tryMergeTokens(JSExponentiation, TT_JsExponentiation))
+      return;
+    if (tryMergeTokens(JSExponentiationEqual, TT_JsExponentiationEqual)) {
+      Tokens.back()->Tok.setKind(tok::starequal);
+      return;
+    }
   }
 
   if (Style.Language == FormatStyle::LK_Java) {
Index: cfe/trunk/unittests/Format/FormatTestJS.cpp
===================================================================
--- cfe/trunk/unittests/Format/FormatTestJS.cpp
+++ cfe/trunk/unittests/Format/FormatTestJS.cpp
@@ -1786,5 +1786,11 @@
                getGoogleJSStyleWithColumns(25));
   verifyFormat("// taze: x from 'location'", getGoogleJSStyleWithColumns(10));
 }
+
+TEST_F(FormatTestJS, Exponentiation) {
+  verifyFormat("squared = x ** 2;");
+  verifyFormat("squared **= 2;");
+}
+
 } // end namespace tooling
 } // end namespace clang