Scrapy: Converting Javascript array to Json on Python

I have been struggling with a site I am scrapping using scrappy.
This site, returns a series of Javascript variables (array) with the products data.
Example:

datos[0] = ["12345","3M YELLOW CAT5E CABLE","6.81","1","A","N","N","N","N","N",0,0,0,0,0,"0","0","0","0","0","P","001-0030","12","40K8957","28396","250","Due: 30-12-1899",0.0000,1,"",''];
datos[1] = ["12346","3M GREEN CAT5E CABLE","7.81","1","A","N","N","N","N","N",0,0,0,0,0,"0","0","0","0","0","P","001-0030","12","40K8957","28396","250","Due: 30-12-1899",0.0000,1,"",''];
...

So on…

Fetching the array into a string with scrapy was easy, since the site response prints the variables.
The problem is I want to transform it into Json so I can process it and store it in a database table.

Normally I would use Javascript’s function Json.stringify to convert it to Json and post it in PHP.

However when using Python’s json.loads and even StringIO I am unable to load the array into json.

Probably is a format error, but I am unable to identify it, since I am not expert in Json nor Python.

EDIT:
I just realize since scrapy is unable to execute Javascript probably the main issue is that the data is just a string. I should format it into a Json format.

Any help is more than welcome.

Thank you.