---
type: "fhir-fhirpath-function"
title: "FHIR FHIRPath Function: %factory.withProperty"
source: "source/fhirpath.html"
---

# FHIR FHIRPath Function: %factory.withProperty

This page is part of **FHIR FHIRPath** (FHIR-specific extensions). Base spec lives at [FHIRPath](/fhirpath).

`%factory.withProperty(instance : T, name : string, value) : T`

Set a property value, and return the new type: `%factory.withProperty(%factory.create(Address), 'http:/acme.com/extension/example', %factory.create(Period))`

Parameters:

-   **instance**: The instance to set the property on
-   **name**: a string value that identifies the property to set
-   **value**: the value of the property

**Return Value:** A copy of the instance of the type with the named property set. Any existing value(s) for the named property will be deleted.

[Back to FHIR FHIRPath](/fhir-fhirpath)