Fix error: "n.data.substring is not a function" (#6000)

* Fix error: "n.data.substring is not a function"

* update CHANGELOG.md

Author: Muhammad-Altabba

CHANGELOG.md

@@ -666,7 +666,7 @@ Released with 1.0.0-beta.37 code base.
 ### Fixed
 
   - Improved the error propagation in `web3-providers-http` package to effectively propagate useful error infomation about failed HTTP connections (#5955)
-
+  - Fix error: "n.data.substring is not a function", that is raised when there is a revert and `web.eth.handleRevert = true` (#6000)
 ### Changed
 
   - `transaction.type` is now formatted to a hex string before being send to provider (#5979)

packages/web3-core-method/src/index.js

@@ -653,7 +653,7 @@ Method.prototype.buildCall = function () {
                 if (!err && method.isRevertReasonString(result)){
                     reasonData = result.substring(10);
                 } else if (err && err.data){
-                    reasonData = err.data.substring(10);
+                    reasonData = (err.data.data || err.data).substring(10);
                 }
 
                 if (reasonData){