diff --git a/src/solidity/types/Int.js b/src/solidity/types/Int.js
index 8a6b22cbf3..747dc6a809 100644
--- a/src/solidity/types/Int.js
+++ b/src/solidity/types/Int.js
@@ -6,23 +6,23 @@ class Int extends ValueType {
   constructor (storageBytes) {
     super(1, storageBytes, 'int')
   }
-}
 
-Int.prototype.decodeFromStorage = function (location, storageContent) {
-  return util.decodeInt(location, storageContent, this.storageBytes, true)
-}
+  decodeFromStorage (location, storageContent) {
+    return util.decodeInt(location, storageContent, this.storageBytes, true)
+  }
 
-Int.prototype.decodeFromStack = function (stackDepth, stack, memory) {
-  if (stackDepth >= stack.length) {
-    return '0'
-  } else {
-    return util.decodeIntFromHex(stack[stack.length - 1 - stackDepth].replace('0x', ''), 32, true)
+  decodeFromStack (stackDepth, stack, memory) {
+    if (stackDepth >= stack.length) {
+      return '0'
+    } else {
+      return util.decodeIntFromHex(stack[stack.length - 1 - stackDepth].replace('0x', ''), 32, true)
+    }
   }
-}
 
-Int.prototype.decodeFromMemory = function (offset, memory) {
-  var value = memory.substr(offset, 64)
-  return util.decodeIntFromHex(value, 32, true)
+  decodeFromMemory (offset, memory) {
+    var value = memory.substr(offset, 64)
+    return util.decodeIntFromHex(value, 32, true)
+  }
 }
 
 module.exports = Int