The end of support for the JavaScript API was announced a couple of years ago.
However, so far any scripts or add-ins that were written using the JavaScript API have continued to run.
Please note that this is set to change, and as of the December release of Fusion 360 they will no longer run at all.
Any script or add-in using the JavaScript API will need to be migrated to either Python or C++.
Please find the official announcement here:
