Reading a Failing FHIRPath Expression and Finding the Type Mismatch
A failing FHIRPath expression rarely fails loud. It returns an empty collection, or a boolean that flips wrong, or a…
Category: Fhirpath Tryout
FHIRPath in Questionnaire Calculations
FHIR Questionnaires use FHIRPath in two related places: calculated expressions on items, and enable-when logic that shows or hides items…
Extension Navigation With FHIRPath: The ext(url) Shortcut
Extensions are how FHIR carries what the base spec did not model, and navigating them is one of the most…
Testing FHIRPath Expressions Against Real Production Resources
A FHIRPath expression that passes on the demo resource in the spec often fails on the payload that actually arrives…
Using FHIRPath in Invariants Without Shooting Yourself in the Foot
Invariants written in FHIRPath are the mechanism by which profiles enforce rules that go beyond cardinality and datatype. They are…
Typical FHIRPath Expressions Worth Memorizing
A handful of FHIRPath expressions come up on every real implementation, and having them at your fingertips saves the trip…
The Collection Semantics That Surprise You at First
FHIRPath collections behave like flattened set-pipelines, and the four or five behaviors that surprise most people at first are worth…
FHIRPath Basics for Someone Who Knows JavaScript
The first FHIRPath expression a JavaScript developer meets looks familiar and then quietly is not. Patient.name.given looks like a chain…