I found this to be an issue with Node 10, did you happen to be running that version? It was already fixed and a new version will be released soon (meanwhile you should be able to play with Node 8).
136 karma · joined May 10, 2018
If you're interested in proposing a solution for the issue you describe, there's already people discussing it here: https://github.com/olistic/warriorjs/issues/69