You checked it still loaded & ran OK before uploading it to SharePoint? And are you still renaming index.html > index.aspx?
otherwise I think it's probably to do with you adding the files to the 'document library', I don't think they work quite like that. it's not something I'm familiar with TBH, you'll have to do a bit of googling to find out the right way to do this. Aside from the possible requirement to change .json > .txt there shouldn't be anything else you need to do to the adapt content.