It becomes part of the add-on when I update the add-on’s POM, I am usually trying to open a PR to the add-on ASAP, but obviously I have to wait for a review (I usually ping @laursen who is really fast at reviewing and merging these PRs, thanks!!).
So I think there is a good chance that it is available in the next snapshot, but if it is not, it should be in the next next snapshot.
EDIT: It’ll be in the next snapshot, my PR was just merged!
New month, new release: Version 4.5.0 has been published.
It brings one enhancement: The Quantity factory and the divide/multiply methods now accept compatible Items as arguments.
You can find the changelog at the openhab-js repo: https://github.com/openhab/openhab-js/blob/v4.5.0/CHANGELOG.md#450.
Two months after the last minor, we have just published a new minor: Version 4.6.0.
It brings several enhancements regarding rules as well as one bugfix.
Have a look at the updated post at the top to get more information, or check the changelog: https://github.com/openhab/openhab-js/blob/v4.6.0/CHANGELOG.md#460.