diff --git a/remix-simulator/src/methods/accounts.js b/remix-simulator/src/methods/accounts.js
index 406069e2e2..c85493aade 100644
--- a/remix-simulator/src/methods/accounts.js
+++ b/remix-simulator/src/methods/accounts.js
@@ -1,6 +1,6 @@
 var Web3 = require('web3')
 
-var Accounts = function(web3) {
+var Accounts = function () {
   this.web3 = new Web3()
   // TODO: make it random and/or use remix-libs
   this.accounts = [this.web3.eth.accounts.create(['abcd'])]
@@ -15,8 +15,8 @@ Accounts.prototype.methods = function () {
   }
 }
 
-Accounts.prototype.eth_accounts = function(payload, cb) {
+Accounts.prototype.eth_accounts = function (payload, cb) {
   return cb(null, this.accounts.map((x) => x.address))
 }
 
-module.exports = Accounts;
+module.exports = Accounts
diff --git a/remix-simulator/src/methods/blocks.js b/remix-simulator/src/methods/blocks.js
index ae99b50713..718070f42c 100644
--- a/remix-simulator/src/methods/blocks.js
+++ b/remix-simulator/src/methods/blocks.js
@@ -1,5 +1,5 @@
 
-var Blocks = function() {
+var Blocks = function () {
 }
 
 Blocks.prototype.methods = function () {
@@ -39,4 +39,4 @@ Blocks.prototype.eth_gasPrice = function (payload, cb) {
   cb(null, 1)
 }
 
-module.exports = Blocks;
+module.exports = Blocks
diff --git a/remix-simulator/src/methods/misc.js b/remix-simulator/src/methods/misc.js
index ffb386c57e..a2fd6db044 100644
--- a/remix-simulator/src/methods/misc.js
+++ b/remix-simulator/src/methods/misc.js
@@ -1,6 +1,6 @@
 var version = require('../../package.json').version
 
-var Misc = function() {
+var Misc = function () {
 }
 
 Misc.prototype.methods = function () {
@@ -13,5 +13,4 @@ Misc.prototype.web3_clientVersion = function (payload, cb) {
   cb(null, 'Remix Simulator/' + version)
 }
 
-
-module.exports = Misc;
+module.exports = Misc
diff --git a/remix-simulator/src/methods/transactions.js b/remix-simulator/src/methods/transactions.js
index 1095f23a2b..987ebdc3f2 100644
--- a/remix-simulator/src/methods/transactions.js
+++ b/remix-simulator/src/methods/transactions.js
@@ -2,8 +2,8 @@ var RemixLib = require('remix-lib')
 var executionContext = RemixLib.execution.executionContext
 var processTx = require('./txProcess.js')
 
-var Transactions = function(accounts) {
-  this.accounts = accounts;
+var Transactions = function (accounts) {
+  this.accounts = accounts
   // TODO: fix me; this is a temporary and very hackish thing just to get the getCode working for now
   this.deployedContracts = {}
 }
@@ -18,12 +18,12 @@ Transactions.prototype.methods = function () {
   }
 }
 
-Transactions.prototype.eth_sendTransaction = function(payload, cb) {
-  processTx(this.accounts, payload, false, cb);
+Transactions.prototype.eth_sendTransaction = function (payload, cb) {
+  processTx(this.accounts, payload, false, cb)
 }
 
-Transactions.prototype.eth_getTransactionReceipt = function(payload, cb) {
-  const self = this;
+Transactions.prototype.eth_getTransactionReceipt = function (payload, cb) {
+  const self = this
   executionContext.web3().eth.getTransactionReceipt(payload.params[0], (error, receipt) => {
     if (error) {
       return cb(error)
@@ -46,18 +46,18 @@ Transactions.prototype.eth_getTransactionReceipt = function(payload, cb) {
   })
 }
 
-Transactions.prototype.eth_estimateGas = function(payload, cb) {
+Transactions.prototype.eth_estimateGas = function (payload, cb) {
   cb(null, 3000000)
 }
 
-Transactions.prototype.eth_getCode = function(payload, cb) {
+Transactions.prototype.eth_getCode = function (payload, cb) {
   let address = payload.params[0]
 
   cb(null, this.deployedContracts[address] || '0x')
 }
 
-Transactions.prototype.eth_call = function(payload, cb) {
+Transactions.prototype.eth_call = function (payload, cb) {
   processTx(this.accounts, payload, true, cb)
 }
 
- module.exports = Transactions;
+module.exports = Transactions
diff --git a/remix-simulator/src/methods/whisper.js b/remix-simulator/src/methods/whisper.js
index b1b3e38ccb..bfd88f43e0 100644
--- a/remix-simulator/src/methods/whisper.js
+++ b/remix-simulator/src/methods/whisper.js
@@ -1,16 +1,15 @@
 
-var Whisper = function() {
+var Whisper = function () {
 }
 
-Whisper.prototype.methods = function() {
+Whisper.prototype.methods = function () {
   return {
     shh_version: this.shh_version.bind(this)
   }
 }
 
-Whisper.prototype.shh_version = function(payload, cb) {
+Whisper.prototype.shh_version = function (payload, cb) {
   cb(null, 5)
 }
 
 module.exports = Whisper
-
diff --git a/remix-simulator/src/provider.js b/remix-simulator/src/provider.js
index ccc48e117b..e8ef2f3e77 100644
--- a/remix-simulator/src/provider.js
+++ b/remix-simulator/src/provider.js
@@ -1,18 +1,14 @@
-var RemixLib = require('remix-lib')
 const log = require('fancy-log')
+const merge = require('merge')
+
 const Accounts = require('./methods/accounts.js')
 const Blocks = require('./methods/blocks.js')
 const Misc = require('./methods/misc.js')
 const Transactions = require('./methods/transactions.js')
 const Whisper = require('./methods/whisper.js')
-const merge = require('merge')
-
-function jsonRPCResponse (id, result) {
-  return {'id': id, 'jsonrpc': '2.0', 'result': result}
-}
 
 var Provider = function () {
-  this.Accounts = new Accounts();
+  this.Accounts = new Accounts()
 
   this.methods = {}
   this.methods = merge(this.methods, this.Accounts.methods())
@@ -24,19 +20,19 @@ var Provider = function () {
 }
 
 Provider.prototype.sendAsync = function (payload, callback) {
-  const self = this
   log.info('payload method is ', payload.method)
 
   let method = this.methods[payload.method]
   if (method) {
     return method.call(method, payload, (err, result) => {
       if (err) {
-        return callback({error: err})
+        return callback(err)
       }
-      callback(null, jsonRPCResponse(payload.id, result))
-    });
+      let response = {'id': payload.id, 'jsonrpc': '2.0', 'result': result}
+      callback(null, response)
+    })
   }
-  callback("unknown method " + payload.method);
+  callback(new Error('unknown method ' + payload.method))
 }
 
 Provider.prototype.isConnected = function () {