add shortenHexData helper

src/lib/helper.js

@@ -2,5 +2,10 @@ module.exports = {
   shortenAddress: function (address, etherBalance) {
     var len = address.length
     return address.slice(0, 5) + '...' + address.slice(len - 5, len) + (etherBalance ? ' (' + etherBalance.toString() + ' ether)' : '')
+  },
+  shortenHexData: function (data) {
+    if (data.length < 5) return data
+    var len = data.length
+    return data.slice(0, 5) + '...' + data.slice(len - 5, len)
   }
 }