Invalid JSON data for parsing - uploader

UPDATE: Sorry, just wrong command! It’s solved

Greeting, I’m new to this and need some help.
I’m using uploader to upload an image (single upload) to specific directory and it success, but the problem is “Invalid JSON data for parsing” shown up.
I applied this with the webix.ajax().post (uploader and form integration), I think the uploader process is done but then it stop with this Invalid thing before able to enter to post process, am i correct? what should I do with this? Thanks