json-diff | Compute the difference between two JSON-serializable Ruby objects

As @Ed Sabol pointed out, the problem was with file characters, and how the files were being read.

the key line to change is readdir $dh to decode_utf8(readdir $dh) this allows Perl to handle the non-Latin (Cyrillic) filenames. The Encode library should also be loaded: use Encode 'decode_utf8';

This doesn't seem to be an error from Signalr. From the error you've provivded, I'm guessing there's a json-diff npm package being used in your project (look in package.json for it).

If it's not supposed to be there (check the original code), remove the code related to json-diff from the Update.modal.ts and CreateEdit.component.ts files.

If it's supposed to be there, make sure it's listed in package.json (otherwise, install it). If it's already installed, delete the package-lock.json file and the node_modules folder, and run npm install again.

If everything fails, and you just want to revert to the original branch code, run git clean -fd && git reset --hard (WARNING: this will remove all un-pushed local changes that you had done to the branch as well as new files that are not tracked by git). Confirm that the package-lock.json and node_modules folder are deleted in your project, and run npm install

i'm not sure if this is your need but