Plugin keywords

Plugins are the pipeline’s only asynchronous stage. There is no fixed plugin keyword: any descriptor key that names a registered plugin calls it, with the key’s value as options.

/publisher: { source: /publisherId, publishers: {} }

The located value flows into the plugin. The plugin’s return value replaces it. With a publishers plugin that looks ids up in a directory and input { "publisherId": "p1" }, the pairing writes the publisher record.

pointer

Core. In a plugin’s options, narrows its result:

/publisherName: { source: /publisherId, publishers: { pointer: /name } }

writes just the record’s name.

Chaining

Multiple plugin keys on one descriptor chain in document order. Each receives the previous plugin’s result as its value.

stdout

Experimental. Prints the value for diagnosis after the mapping completes. It never affects the result, and it carries no tested example because its output is a side effect.

Signatures and the extension contract: Write extensions.