Undefined offset error (fresh install)

[nunodonato]

Hi
I've just installed this package in a laravel 7 app (php 7.3). All ok, except when I run php artisan lang:js
this is what I get:

In LangJsGenerator.php line 215:
                       
  Undefined offset: 3  

The only thing different in this project is that the vendor folder is outside the main project folder. Not sure if could be related
Any tips?

[nunodonato]

Further digging into it revealed its a problem with a vendor translation that has a .php file mixed with other .json files.
The code that converts the file names to keys is expecting a 4 character extension, and gets confused when it meets the .php file

this is in LangJsGenerator.php
$key = substr($pathName, 0, -4);