method signature length defined

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/contract.js b/lib/contract.js
index 1a03849bf..4cb202255 100644
--- a/lib/contract.js
+++ b/lib/contract.js
@@ -27,6 +27,9 @@ if (process.env.NODE_ENV !== 'build') {
 
 var abi = require('./abi');
 
+// method signature length in bytes
+var ETH_METHOD_SIGNATURE_LENGTH = 4;
+
 var contract = function (address, desc) {
     var inputParser = abi.inputParser(desc);
     var outputParser = abi.outputParser(desc);
@@ -47,7 +50,7 @@ var contract = function (address, desc) {
                     extra = extra || {};
                     extra.to = address;
                     return abi.methodSignature(desc, method.name).then(function (signature) {
-                        extra.data = signature.slice(0, 10) + parsed;
+                        extra.data = signature.slice(0, 2 + ETH_METHOD_SIGNATURE_LENGTH * 2) + parsed;
                         return web3.eth.call(extra).then(onSuccess);
                     });
                 },