diff --git a/js/js.translator/src/org/jetbrains/k2js/translate/context/DynamicContext.java b/js/js.translator/src/org/jetbrains/k2js/translate/context/DynamicContext.java
index ed0028287ac..aa1d08c6496 100644
--- a/js/js.translator/src/org/jetbrains/k2js/translate/context/DynamicContext.java
+++ b/js/js.translator/src/org/jetbrains/k2js/translate/context/DynamicContext.java
@@ -53,8 +53,13 @@ public final class DynamicContext {
 
     @NotNull
     public TemporaryVariable declareTemporary(@NotNull JsExpression initExpression) {
+        return declareTemporary(initExpression, false);
+    }
+
+    @NotNull
+    public TemporaryVariable declareTemporary(@NotNull JsExpression initExpression, boolean initialize) {
         JsName temporaryName = currentScope.declareTemporary();
-        JsVars temporaryDeclaration = newVar(temporaryName, /*no init expression in var statement*/ null);
+        JsVars temporaryDeclaration = newVar(temporaryName, initialize ? initExpression : null);
         addVarDeclaration(jsBlock(), temporaryDeclaration);
         return new TemporaryVariable(temporaryName, initExpression);
     }
diff --git a/js/js.translator/src/org/jetbrains/k2js/translate/context/TranslationContext.java b/js/js.translator/src/org/jetbrains/k2js/translate/context/TranslationContext.java
index 07fc4f3ce79..26e8f33ec4c 100644
--- a/js/js.translator/src/org/jetbrains/k2js/translate/context/TranslationContext.java
+++ b/js/js.translator/src/org/jetbrains/k2js/translate/context/TranslationContext.java
@@ -157,6 +157,11 @@ public final class TranslationContext {
         return dynamicContext.declareTemporary(initExpression);
     }
 
+    @NotNull
+    public TemporaryVariable declareTemporary(@NotNull JsExpression initExpression, boolean initialize) {
+        return dynamicContext.declareTemporary(initExpression, initialize);
+    }
+
     @NotNull
     public Namer namer() {
         return staticContext.getNamer();
diff --git a/js/js.translator/src/org/jetbrains/k2js/translate/operation/UnaryOperationTranslator.java b/js/js.translator/src/org/jetbrains/k2js/translate/operation/UnaryOperationTranslator.java
index 8d5bba28ff9..43364bdc76a 100644
--- a/js/js.translator/src/org/jetbrains/k2js/translate/operation/UnaryOperationTranslator.java
+++ b/js/js.translator/src/org/jetbrains/k2js/translate/operation/UnaryOperationTranslator.java
@@ -19,9 +19,11 @@ package org.jetbrains.k2js.translate.operation;
 import com.google.dart.compiler.backend.js.ast.JsBinaryOperation;
 import com.google.dart.compiler.backend.js.ast.JsConditional;
 import com.google.dart.compiler.backend.js.ast.JsExpression;
+import com.google.dart.compiler.backend.js.ast.JsNameRef;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jet.lang.psi.JetUnaryExpression;
 import org.jetbrains.jet.lexer.JetTokens;
+import org.jetbrains.k2js.translate.context.TemporaryVariable;
 import org.jetbrains.k2js.translate.context.TranslationContext;
 import org.jetbrains.k2js.translate.reference.CallBuilder;
 import org.jetbrains.k2js.translate.reference.CallType;
@@ -62,9 +64,9 @@ public final class UnaryOperationTranslator {
 
     @NotNull
     private static JsExpression translateExclExclOperator(@NotNull JetUnaryExpression expression, @NotNull TranslationContext context) {
-        JsExpression translatedExpression = translateAsExpression(getBaseExpression(expression), context);
-        JsBinaryOperation notNullCheck = notNullCheck(context, translatedExpression);
-        return new JsConditional(notNullCheck, translatedExpression, context.namer().throwNPEFunctionCall());
+        JsNameRef cachedValue = context.declareTemporary(translateAsExpression(getBaseExpression(expression), context), true).reference();
+        JsBinaryOperation notNullCheck = notNullCheck(context, cachedValue);
+        return new JsConditional(notNullCheck, cachedValue, context.namer().throwNPEFunctionCall());
     }
 
     @NotNull