Enhancement : Expression Engine : Set Value Effect Redesign

[lattln]

Context

This ticket tracks the follow-up work needed for the setValue effect on the
feature/add-fhir-requirements branch.

Problem Statement

The current setValue implementation mixes two separate concerns:

1. When the rule should fire.
2. What value should be assigned when it does fire.

That design works for simple expression-based cases, but it breaks down for:

• Conditional set-value rules where a non-expression condition gates the rule.
• Selection fields where the target value should be an optionId, not a free-form expression.
• FHIR import mapping, where initialExpression / related inputs should round-trip into a more explicit setValue payload.

Proposed Solution

Add a dedicated setValue payload to each rule instead of encoding the value source inside the condition list.

Suggested shape:

type SetValuePayload =
  | { type: 'expression'; expression: string }
  | { type: 'option'; optionId: string };

interface Rule {
  effect: EffectType;
  conditions: Condition[];
  setValue?: SetValuePayload;
}

Implementation Checklist

• Update packages/core/src/lib/types.ts to add SetValuePayload and setValue? on Rule
• Update packages/core/src/lib/logic/resolve.ts so resolveSetValue() reads rule.setValue first
• Keep backward compatibility for existing expression-only rules during migration
• Update selection field handling so computed option values map to the correct selected state
• Update packages/builder/src/lib/components/edit-panel/LogicEditor.tsx to expose the right authoring UI per field type
• Update packages/adapters/src/fhir/fhir-adapter.ts so imported FHIR expressions map into the new setValue shape
• Add or update unit tests around resolveSetValue() and rule hydration

Success Criteria

• A field can use a field-based condition gate and still resolve a separate computed value
• Selection fields can be driven by an optionId payload instead of a free-form expression
• Existing expression-based setValue rules continue to work
• FHIR import/export behavior preserves the intent of initialExpression style rules

Related Files

• packages/core/src/lib/types.ts
• packages/core/src/lib/logic/resolve.ts
• packages/core/src/lib/field-component-props.ts
• packages/builder/src/lib/components/edit-panel/LogicEditor.tsx
• packages/adapters/src/fhir/fhir-adapter.ts

[redmine-bridge-mieweb]

Redmine Ticket: #156864 created from GitHub Issue