Jetscript is a fairly simplistic yet powerful mapping language to implement Single Message Transformations (SMTs). It is designed to be embedded into NATS, but can be used in any context where a simple mapping language is needed.
- Simple syntax
- Support for maps; the equivalent of a function in other languages
- One incoming message to 0-many resulting messages
- exec - Subscribe to a nats subject and execute a jetscript file on each message
- lint - Lint a jetscript file for syntax errors
- push - Push a jetscript file to a nats the Nats Jetstream Object Store
- pull - Pull a jetscript file from the Nats Jetstream Object Store
You can write your jetscript in a file locally and lint it with the jetstream lint <your-file> command. If you want
to apply your jetscript to messages in a nats subject, you first need to push it to the Jetstream Object Store with
the jetstream push --path <path-in-object-store> <your-file> command. Then launch the
jetstream exec --subject <subject> --path <path-in-object-store> command to start processing messages.