diff --git a/src/app/ui/universal-dapp-ui.js b/src/app/ui/universal-dapp-ui.js
index 226df2393d..f262ca51cb 100644
--- a/src/app/ui/universal-dapp-ui.js
+++ b/src/app/ui/universal-dapp-ui.js
@@ -1,33 +1,27 @@
 /* global */
 'use strict'
 
-var $ = require('jquery')
-var yo = require('yo-yo')
-var ethJSUtil = require('ethereumjs-util')
-var BN = ethJSUtil.BN
-var helper = require('../../lib/helper')
-var copyToClipboard = require('./copy-to-clipboard')
-var css = require('../../universal-dapp-styles')
-var MultiParamManager = require('./multiParamManager')
-var remixLib = require('remix-lib')
-var txFormat = remixLib.execution.txFormat
-var txHelper = remixLib.execution.txHelper
-
-var confirmDialog = require('./confirmDialog')
-var modalCustom = require('./modal-dialog-custom')
-var modalDialog = require('./modaldialog')
-var TreeView = require('./TreeView')
-
-function UniversalDAppUI (blockchain, logCallback) {
-  this.blockchain = blockchain
-  this.logCallback = logCallback
-  this.compilerData = {contractsDetails: {}}
-}
+const $ = require('jquery')
+const yo = require('yo-yo')
+const ethJSUtil = require('ethereumjs-util')
+const BN = ethJSUtil.BN
+const helper = require('../../lib/helper')
+const copyToClipboard = require('./copy-to-clipboard')
+const css = require('../../universal-dapp-styles')
+const MultiParamManager = require('./multiParamManager')
+const remixLib = require('remix-lib')
+const txFormat = remixLib.execution.txFormat
+const txHelper = remixLib.execution.txHelper
+
+const confirmDialog = require('./confirmDialog')
+const modalCustom = require('./modal-dialog-custom')
+const modalDialog = require('./modaldialog')
+const TreeView = require('./TreeView')
 
 function decodeResponseToTreeView (response, fnabi) {
-  var treeView = new TreeView({
+  const treeView = new TreeView({
     extractData: (item, parent, key) => {
-      var ret = {}
+      let ret = {}
       if (BN.isBN(item)) {
         ret.self = item.toString(10)
         ret.children = []
@@ -40,27 +34,42 @@ function decodeResponseToTreeView (response, fnabi) {
   return treeView.render(txFormat.decodeResponse(response, fnabi))
 }
 
-UniversalDAppUI.prototype.renderInstance = function (contract, address, contractName) {
-  var noInstances = document.querySelector('[class^="noInstancesText"]')
-  if (noInstances) {
-    noInstances.parentNode.removeChild(noInstances)
+class UniversalDAppUI {
+
+  constructor (blockchain, logCallback) {
+    this.blockchain = blockchain
+    this.logCallback = logCallback
+    this.compilerData = { contractsDetails: {} }
+  }
+
+  renderInstance (contract, address, contractName) {
+    const noInstances = document.querySelector('[class^="noInstancesText"]')
+    if (noInstances) {
+      noInstances.parentNode.removeChild(noInstances)
+    }
+    const abi = txHelper.sortAbiFunction(contract.abi)
+    return this.renderInstanceFromABI(abi, address, contractName)
   }
-  const abi = txHelper.sortAbiFunction(contract.abi)
-  return this.renderInstanceFromABI(abi, address, contractName)
-}
 
-// TODO this function was named before "appendChild".
-// this will render an instance: contract name, contract address, and all the public functions
-// basically this has to be called for the "atAddress" (line 393) and when a contract creation succeed
-// this returns a DOM element
-UniversalDAppUI.prototype.renderInstanceFromABI = function (contractABI, address, contractName) {
-  address = (address.slice(0, 2) === '0x' ? '' : '0x') + address.toString('hex')
-  address = ethJSUtil.toChecksumAddress(address)
-  var instance = yo`<div class="instance ${css.instance} ${css.hidesub}" id="instance${address}"></div>`
-  const context = this.blockchain.context()
-
-  var shortAddress = helper.shortenAddress(address)
-  var title = yo`
+  // TODO this function was named before "appendChild".
+  // this will render an instance: contract name, contract address, and all the public functions
+  // basically this has to be called for the "atAddress" (line 393) and when a contract creation succeed
+  // this returns a DOM element
+  renderInstanceFromABI (contractABI, address, contractName) {
+    address = (address.slice(0, 2) === '0x' ? '' : '0x') + address.toString('hex')
+    address = ethJSUtil.toChecksumAddress(address)
+    const instance = yo`<div class="instance ${css.instance} ${css.hidesub}" id="instance${address}"></div>`
+    const context = this.blockchain.context()
+
+    function toggleClass (e) {
+      $(instance).toggleClass(`${css.hidesub}`)
+      // e.currentTarget.querySelector('i')
+      e.currentTarget.querySelector('i').classList.toggle(`fa-angle-right`)
+      e.currentTarget.querySelector('i').classList.toggle(`fa-angle-down`)
+    }
+
+    const shortAddress = helper.shortenAddress(address)
+    const title = yo`
     <div class="${css.title} alert alert-secondary p-2">
       <button class="btn ${css.titleExpander}" onclick="${(e) => { toggleClass(e) }}">
         <i class="fas fa-angle-right" aria-hidden="true"></i>
@@ -78,166 +87,155 @@ UniversalDAppUI.prototype.renderInstanceFromABI = function (contractABI, address
     </div>
   `
 
-  var close = yo`
+    const close = yo`
     <button
       class="${css.udappClose} p-1 btn btn-secondary"
-      onclick=${remove}
+      onclick=${() => { instance.remove() }}
       title="Remove from the list"
     >
       <i class="${css.closeIcon} fas fa-times" aria-hidden="true"></i>
     </button>`
-  title.querySelector('.btn-group').appendChild(close)
+    title.querySelector('.btn-group').appendChild(close)
 
-  var contractActionsWrapper = yo`
+    const contractActionsWrapper = yo`
     <div class="${css.cActionsWrapper}">
     </div>
   `
 
-  function remove () {
-    instance.remove()
-    // @TODO perhaps add a callack here to warn the caller that the instance has been removed
-  }
-
-  function toggleClass (e) {
-    $(instance).toggleClass(`${css.hidesub}`)
-    // e.currentTarget.querySelector('i')
-    e.currentTarget.querySelector('i').classList.toggle(`fa-angle-right`)
-    e.currentTarget.querySelector('i').classList.toggle(`fa-angle-down`)
-  }
+    instance.appendChild(title)
+    instance.appendChild(contractActionsWrapper)
 
-  instance.appendChild(title)
-  instance.appendChild(contractActionsWrapper)
+    // Add the fallback function
+    const fallback = txHelper.getFallbackInterface(contractABI)
 
-  // Add the fallback function
-  const fallback = txHelper.getFallbackInterface(contractABI)
-
-  if (fallback) {
-    contractActionsWrapper.appendChild(this.getCallButton({
-      funABI: fallback,
-      address: address,
-      contractAbi: contractABI,
-      contractName: contractName
-    }))
-  }
-
-  $.each(contractABI, (i, funABI) => {
-    if (funABI.type !== 'function') {
-      return
+    if (fallback) {
+      contractActionsWrapper.appendChild(this.getCallButton({
+        funABI: fallback,
+        address: address,
+        contractAbi: contractABI,
+        contractName: contractName
+      }))
     }
-    // @todo getData cannot be used with overloaded functions
-    contractActionsWrapper.appendChild(this.getCallButton({
-      funABI: funABI,
-      address: address,
-      contractAbi: contractABI,
-      contractName: contractName
-    }))
-  })
 
-  return instance
-}
+    $.each(contractABI, (i, funABI) => {
+      if (funABI.type !== 'function') {
+        return
+      }
+      // @todo getData cannot be used with overloaded functions
+      contractActionsWrapper.appendChild(this.getCallButton({
+        funABI: funABI,
+        address: address,
+        contractAbi: contractABI,
+        contractName: contractName
+      }))
+    })
+
+    return instance
+  }
 
-UniversalDAppUI.prototype.getConfirmationCb = function (modalDialog, confirmDialog) {
-  const confirmationCb = (network, tx, gasEstimation, continueTxExecution, cancelCb) => {
-    if (network.name !== 'Main') {
-      return continueTxExecution(null)
-    }
-    const amount = this.blockchain.fromWei(tx.value, true, 'ether')
-    const content = confirmDialog(tx, amount, gasEstimation, null, this.blockchain.determineGasFees(tx), this.blockchain.determineGasPrice)
-
-    modalDialog('Confirm transaction', content,
-      {
-        label: 'Confirm',
-        fn: () => {
-          this.config.setUnpersistedProperty('doNotShowTransactionConfirmationAgain', content.querySelector('input#confirmsetting').checked)
-          // TODO: check if this is check is still valid given the refactor
-          if (!content.gasPriceStatus) {
-            cancelCb('Given gas price is not correct')
-          } else {
-            var gasPrice = this.blockchain.toWei(content.querySelector('#gasprice').value, 'gwei')
-            continueTxExecution(gasPrice)
+  getConfirmationCb (modalDialog, confirmDialog) {
+    const confirmationCb = (network, tx, gasEstimation, continueTxExecution, cancelCb) => {
+      if (network.name !== 'Main') {
+        return continueTxExecution(null)
+      }
+      const amount = this.blockchain.fromWei(tx.value, true, 'ether')
+      const content = confirmDialog(tx, amount, gasEstimation, null, this.blockchain.determineGasFees(tx), this.blockchain.determineGasPrice)
+
+      modalDialog('Confirm transaction', content,
+        {
+          label: 'Confirm',
+          fn: () => {
+            this.config.setUnpersistedProperty('doNotShowTransactionConfirmationAgain', content.querySelector('input#confirmsetting').checked)
+            // TODO: check if this is check is still valid given the refactor
+            if (!content.gasPriceStatus) {
+              cancelCb('Given gas price is not correct')
+            } else {
+              const gasPrice = this.blockchain.toWei(content.querySelector('#gasprice').value, 'gwei')
+              continueTxExecution(gasPrice)
+            }
+          }
+        }, {
+          label: 'Cancel',
+          fn: () => {
+            return cancelCb('Transaction canceled by user.')
           }
         }
-      }, {
-        label: 'Cancel',
-        fn: () => {
-          return cancelCb('Transaction canceled by user.')
-        }
-      }
-    )
+      )
+    }
+
+    return confirmationCb
   }
 
-  return confirmationCb
-}
+  // TODO this is used by renderInstance when a new instance is displayed.
+  // this returns a DOM element.
+  getCallButton (args) {
+    // args.funABI, args.address [fun only]
+    // args.contractName [constr only]
+    const lookupOnly = args.funABI.stateMutability === 'view' || args.funABI.stateMutability === 'pure' || args.funABI.constant
 
-// TODO this is used by renderInstance when a new instance is displayed.
-// this returns a DOM element.
-UniversalDAppUI.prototype.getCallButton = function (args) {
-  let self = this
-  // args.funABI, args.address [fun only]
-  // args.contractName [constr only]
-  const lookupOnly = args.funABI.stateMutability === 'view' || args.funABI.stateMutability === 'pure' || args.funABI.constant
-
-  var outputOverride = yo`<div class=${css.value}></div>` // show return value
-
-  function clickButton (valArr, inputsValues) {
-    let logMsg
-    if (!lookupOnly) {
-      logMsg = `call to ${args.contractName}.${(args.funABI.name) ? args.funABI.name : '(fallback)'}`
-    } else {
-      logMsg = `transact to ${args.contractName}.${(args.funABI.name) ? args.funABI.name : '(fallback)'}`
-    }
+    const outputOverride = yo`<div class=${css.value}></div>` // show return value
 
-    const confirmationCb = self.getConfirmationCb(modalDialog, confirmDialog)
-    const continueCb = (error, continueTxExecution, cancelCb) => {
-      if (error) {
-        const msg = typeof error !== 'string' ? error.message : error
-        modalDialog(
-          'Gas estimation failed',
-          yo`
+    const clickButton = (valArr, inputsValues) => {
+      let logMsg
+      if (!lookupOnly) {
+        logMsg = `call to ${args.contractName}.${(args.funABI.name) ? args.funABI.name : '(fallback)'}`
+      } else {
+        logMsg = `transact to ${args.contractName}.${(args.funABI.name) ? args.funABI.name : '(fallback)'}`
+      }
+
+      const confirmationCb = this.getConfirmationCb(modalDialog, confirmDialog)
+      const continueCb = (error, continueTxExecution, cancelCb) => {
+        if (error) {
+          const msg = typeof error !== 'string' ? error.message : error
+          modalDialog(
+            'Gas estimation failed',
+            yo`
             <div>Gas estimation errored with the following message (see below).
             The transaction execution will likely fail. Do you want to force sending? <br>${msg}</div>
           `,
-          {
-            label: 'Send Transaction',
-            fn: () => continueTxExecution()
-          },
-          {
-            label: 'Cancel Transaction',
-            fn: () => cancelCb()
-          }
-        )
-      } else {
-        continueTxExecution()
+            {
+              label: 'Send Transaction',
+              fn: () => continueTxExecution()
+            },
+            {
+              label: 'Cancel Transaction',
+              fn: () => cancelCb()
+            }
+          )
+        } else {
+          continueTxExecution()
+        }
       }
-    }
 
-    const outputCb = (returnValue) => {
-      const decoded = decodeResponseToTreeView(returnValue, args.funABI)
-      outputOverride.innerHTML = ''
-      outputOverride.appendChild(decoded)
-    }
+      const outputCb = (returnValue) => {
+        const decoded = decodeResponseToTreeView(returnValue, args.funABI)
+        outputOverride.innerHTML = ''
+        outputOverride.appendChild(decoded)
+      }
+
+      const promptCb = (okCb, cancelCb) => {
+        modalCustom.promptPassphrase('Passphrase requested', 'Personal mode is enabled. Please provide passphrase of account', '', okCb, cancelCb)
+      }
 
-    const promptCb = (okCb, cancelCb) => {
-      modalCustom.promptPassphrase('Passphrase requested', 'Personal mode is enabled. Please provide passphrase of account', '', okCb, cancelCb)
+      const callType = args.funABI.type !== 'fallback' ? inputsValues : ''
+      this.blockchain.runOrCallContractMethod(args.contractName, args.contractAbi, args.funABI, inputsValues, args.address, callType, lookupOnly, logMsg, this.logCallback, outputCb, confirmationCb, continueCb, promptCb)
     }
 
-    const callType = args.funABI.type !== 'fallback' ? inputsValues : ''
-    self.blockchain.runOrCallContractMethod(args.contractName, args.contractAbi, args.funABI, inputsValues, args.address, callType, lookupOnly, logMsg, self.logCallback, outputCb, confirmationCb, continueCb, promptCb)
-  }
+    let inputs = ''
+    if (args.funABI.inputs) {
+      inputs = txHelper.inputParametersDeclarationToString(args.funABI.inputs)
+    }
 
-  let inputs = ''
-  if (args.funABI.inputs) {
-    inputs = txHelper.inputParametersDeclarationToString(args.funABI.inputs)
-  }
+    const multiParamManager = new MultiParamManager(lookupOnly, args.funABI, (valArray, inputsValues, domEl) => {
+      clickButton(valArray, inputsValues, domEl)
+    }, inputs)
 
-  const multiParamManager = new MultiParamManager(lookupOnly, args.funABI, (valArray, inputsValues, domEl) => {
-    clickButton(valArray, inputsValues, domEl)
-  }, inputs)
+    const contractActionsContainer = yo`<div class="${css.contractActionsContainer}" >${multiParamManager.render()}</div>`
+    contractActionsContainer.appendChild(outputOverride)
 
-  const contractActionsContainer = yo`<div class="${css.contractActionsContainer}" >${multiParamManager.render()}</div>`
-  contractActionsContainer.appendChild(outputOverride)
+    return contractActionsContainer
+  }
 
-  return contractActionsContainer
 }
 
 module.exports = UniversalDAppUI