Implementation of Undo-Redo functionality for your fabricjs project.
By saving Canvas States as JSON. Whenever a user adds or modifies an object in the Canvas, it will save the changed canvas state and maintain it in an array. This array is then manipulated whenever user clicks on Undo or Redo button.
This feature can be implemented with almost all events provided by fabricjs library. For demonstrative purpose, I have chosen only two events: object:added and object:modified.
A note of caution:
If Canvas becomes too heavy with too many objects, rendering can take time when Undoing or Redoing.
https://jsfiddle.net/abhi47/rwdpf3nL/29/
Licensed under the MIT license.