How to fix SPIFFS_write error(-10001): File system is full.

Are you using Angular and seeing this error message? See How to make Angular work with ESP32 SPIFFS / ESPAsyncWebserver

The error message

SPIFFS_write error(-10001): File system is full.

should be mostly self-explanatory:

The files you are trying to put into the image exceed the maximum size of the filesystem image.

There are two possible solutions:

• Decrease the size of the files, either by minifying files where this is possible, or removing some files altogether.
• Increase the allowable size of the filesystem image e.g. by using a ESP32 module with more flash (e.g. 8MB instead of 4MB), and/or using a partition table with a larger file partition.