I've been playing with the ESP8266 as a Web Server, and hence have to upload my web pages to SPIFFS all the time.
I used to use the Arduino IDE and the SPIFFS tool to do my work, but the Arduino IDE is not really for bigger things than Blink.ino. I found VSCode is wonderful for writing/debugging Node/Web Server work, and it has great Arduino/ESP8266 support through the official plugin. The only thing missing was the ESP8266FS uploader.
So, here's the first beta version of the MKSPIFFS wrapper for VSCode. I have it working on my Windows machine, and most of it localized for my Mac and Linux boxes, so I should have a final release version running soon.
I plan to fix the espota.py stuff next then add download/unpack functionality.
How is everyone else managing SPIFFS? I haven't found much user workflow discussion.
Github: https://github.com/kash4kev/vscode-esp8266fs
VSCode: https://marketplace.visualstudio.com/items?itemName=kash4kev.vscode-esp8266fs
or search for "ESP8266FS" in the VSCode Extensions.