Fix for #140 do not allow undefined google var

[ni-oschachtschneider]

This will check if the variable is defined before trying to use it. The eslint rule did not seem to take effect inside a GH Actions pipeline.

[ErrorPro]

@ni-oschachtschneider Not sure what exactly you are changing. There's src folder that has the source files, please modify those ones and use npm run build to build the lib files. Once it's there we can merge it and publish