Supplied names

Gives core the names Smart Forms population binds to the results of a form's sourceQueries, so expressions can reference them, and sdc/undefined-variable accepts them without a hostVariables entry in the config.

The plugin's hostVariables hook is part of the plugin contract. For each Questionnaire, core calls it before the analysis and adds its names to the config's hostVariables. It is called whether or not the plugin's rules are on: listing the plugin activates its names, and rule settings control only its findings. A declaration of the same name in the form still wins.

The names come from the Population model:

• A reference to a contained resource, #PrePopQuery, is named PrePopQuery. It is supplied when the first contained resource with that id is a Bundle with an entry element, even an empty one.
• Any other non-empty reference, such as Observation?code=…, is named sourceQuery<i>, where i counts every sourceQueries extension with a reference from 0. It is supplied assuming the fetch succeeds.
• Nothing is supplied when the form's subjectType is set and lacks Patient, because population stops before reading sourceQueries.
• Never supplied: an empty or display-only reference, # alone, a reference to a contained resource that is not such a Bundle, and #%x, which population binds as %x.

Core drops any name that FHIRPath, FHIR or SDC already defines. A hook that throws, returns a promise or returns something other than a list of names stops the run with PLUGIN_CRASH, which names the plugin.

Names your application passes to the renderer itself belong in hostVariables in the config. Don't list the sourceQueries names there: listing a name the plugin does not supply claims the application supplies it, which usually hides a failure instead of fixing it.

The names it supplies in the plugin README also covers the limits, such as the sourceQueries Bundle entries the Smart Forms app never fills.

Schema

Code

• src/host-variables.ts: hostVariables, the hook, which returns the names of population(input).sourceQueries.
• src/index.ts: registers the hook on the plugin.
• src/population.ts and src/source-queries.ts: which sourceQueries population binds, and their names.
• In core, run/host-variables.ts calls the hook and checks its result, and plugins/contract.ts defines hostVariables and HostVariablesInput.
• test/reproduction/populate-source-queries.test.ts reproduces the names against populate 4.7.1.