diff --git a/remix-debug/src/solidity-decoder/types/Mapping.js b/remix-debug/src/solidity-decoder/types/Mapping.js
index d8db00b6a4..325b5e2f4f 100644
--- a/remix-debug/src/solidity-decoder/types/Mapping.js
+++ b/remix-debug/src/solidity-decoder/types/Mapping.js
@@ -13,7 +13,6 @@ class Mapping extends RefType {
 
   async decodeFromStorage (location, storageResolver) {
     var corrections = this.valueType.members ? this.valueType.members.map((value) => { return value.storagelocation }) : []
-     
     if (!this.initialDecodedState) { // cache the decoded initial storage
       var mappingsInitialPreimages
       try {
diff --git a/remix-debug/src/solidity-decoder/types/util.js b/remix-debug/src/solidity-decoder/types/util.js
index f2bed8ab82..5abb3198c4 100644
--- a/remix-debug/src/solidity-decoder/types/util.js
+++ b/remix-debug/src/solidity-decoder/types/util.js
@@ -9,6 +9,7 @@ module.exports = {
   extractHexByteSlice: extractHexByteSlice,
   toBN: toBN,
   add: add,
+  sub: sub,
   extractLocation: extractLocation,
   removeLocation: removeLocation,
   normalizeHex: normalizeHex,
diff --git a/remix-debug/src/storage/storageViewer.js b/remix-debug/src/storage/storageViewer.js
index 1c448882aa..a5c9e4d7ea 100644
--- a/remix-debug/src/storage/storageViewer.js
+++ b/remix-debug/src/storage/storageViewer.js
@@ -97,7 +97,7 @@ class StorageViewer {
   async mappingsLocation (corrections) {
     if (!this.currentMappingsLocationPromise) {
       this.currentMappingsLocationPromise = new Promise((resolve, reject) => {
-        this.extractMappingsLocationChanges(this.storageChanges, corrections,  (error, mappingsLocationChanges) => {
+        this.extractMappingsLocationChanges(this.storageChanges, corrections, (error, mappingsLocationChanges) => {
           if (error) {
             reject(error)
           } else {
@@ -111,7 +111,6 @@ class StorageViewer {
 
   /**
     * retrieve mapping location changes from the storage changes.
-    
     * @param {Map} storageChanges
     * @param {Array} corrections - used in case the calculated sha3 has been modifyed before SSTORE (notably used for struct in mapping).
     */