diff --git a/libs/remix-debug/src/storage/mappingPreimages.ts b/libs/remix-debug/src/storage/mappingPreimages.ts
index 5978946083..a28e7f9208 100644
--- a/libs/remix-debug/src/storage/mappingPreimages.ts
+++ b/libs/remix-debug/src/storage/mappingPreimages.ts
@@ -1,4 +1,4 @@
-const util = require('../solidity-decoder/types/util')
+import { sub } from '../solidity-decoder/types/util'
 
 /**
   * extract the mappings location from the storage
@@ -17,7 +17,7 @@ export async function decodeMappingsKeys (web3, storage, corrections) {
     try {
       const key = storage[hashedLoc].key
       for (let k in corrections) {
-        const corrected = util.sub(key, corrections[k].slot).toString(16)
+        const corrected = sub(key, corrections[k].slot).toString(16)
         preimage = await getPreimage(web3, '0x' + corrected)
         if (preimage) break
       }
diff --git a/libs/remix-debug/src/storage/storageResolver.ts b/libs/remix-debug/src/storage/storageResolver.ts
index 060657e0e1..998eb84b3e 100644
--- a/libs/remix-debug/src/storage/storageResolver.ts
+++ b/libs/remix-debug/src/storage/storageResolver.ts
@@ -1,6 +1,6 @@
 'use strict'
-const traceHelper = require('../trace/traceHelper')
-const mappingPreimages = require('./mappingPreimages')
+import { isContractCreation } from '../trace/traceHelper'
+import { decodeMappingsKeys } from './mappingPreimages'
 
 /**
   * Basically one instance is created for one debugging session.
@@ -50,7 +50,7 @@ export class StorageResolver {
       return this.preimagesMappingByAddress[address]
     }
     const storage = await this.storageRange(tx, stepIndex, address)
-    const mappings = mappingPreimages.decodeMappingsKeys(this.web3, storage, corrections)
+    const mappings = decodeMappingsKeys(this.web3, storage, corrections)
     this.preimagesMappingByAddress[address] = mappings
     return mappings
   }
@@ -130,7 +130,7 @@ export class StorageResolver {
 
   storageRangeWeb3Call (tx, address, start, maxSize): Promise<Array<unknown>> {
     return new Promise((resolve, reject) => {
-      if (traceHelper.isContractCreation(address)) {
+      if (isContractCreation(address)) {
         resolve([{}, null])
       } else {
         this.web3.debug.storageRangeAt(
diff --git a/libs/remix-debug/src/storage/storageViewer.ts b/libs/remix-debug/src/storage/storageViewer.ts
index b26da0a864..502b636cfb 100644
--- a/libs/remix-debug/src/storage/storageViewer.ts
+++ b/libs/remix-debug/src/storage/storageViewer.ts
@@ -1,7 +1,6 @@
 'use strict'
-const remixLib = require('@remix-project/remix-lib')
-const util = remixLib.util
-const mappingPreimages = require('./mappingPreimages')
+import { util } from '@remix-project/remix-lib'
+import { decodeMappingsKeys } from './mappingPreimages'
 
  /**
    * easier access to the storage resolver
@@ -102,7 +101,7 @@ export class StorageViewer {
     if (this.mappingsLocationChanges) {
       return this.mappingsLocationChanges
     }
-    const mappings = mappingPreimages.decodeMappingsKeys(this.web3, storageChanges, corrections)
+    const mappings = decodeMappingsKeys(this.web3, storageChanges, corrections)
     this.mappingsLocationChanges = mappings
     return this.mappingsLocationChanges
   }