diff --git a/lib/src/utils/utils.dart b/lib/src/utils/utils.dart
index fbc4ed6..e20ca26 100644
--- a/lib/src/utils/utils.dart
+++ b/lib/src/utils/utils.dart
@@ -141,5 +141,5 @@ bool isExpectConversion(int tag) {
 const bool kIsWeb = identical(0, 0.0);
 
 bool isWebDouble(Object a) {
-  return (a as double).toInt() == a;
+  return a is double && a.toInt() == a;
 }
diff --git a/lib/src/value/value.dart b/lib/src/value/value.dart
index 9cbd1da..d5a4d21 100644
--- a/lib/src/value/value.dart
+++ b/lib/src/value/value.dart
@@ -62,8 +62,8 @@ abstract class CborValue {
       return CborNull();
     } else if (object is CborValue) {
       return object;
-    } else if (!kIsWeb && object is double || kIsWeb && isWebDouble(object)) {
-      return CborFloat(object as double);
+    } else if (object is double && (!kIsWeb || kIsWeb && isWebDouble(object))) {
+      return CborFloat(object);
     } else if (object is int) {
       return CborSmallInt(object);
     } else if (object is BigInt) {