ValueSet $expand Operation

Medplum implements the FHIR $expand operation

This operation may be used during design and development to validate application design. It can also be used at run-time. One possible use might be that a client asks the server whether a proposed update is valid as the user is editing a dialog and displays an updated error to the user. The operation can be used as part of a light-weight two phase commit protocol but there is no expectation that the server will hold the content of the resource after this operation is used, or that the server guarantees to successfully perform an actual create, update or delete after the validation operation completes.

Invoke the $expand operation

[base]/ValueSet/$expand

Parameters

Name	Type	Description	Required
url	string	The URL of the value set to expand.	Yes
filter	string	A filter to apply to the value set.	No
offset	number	The offset to start the expansion.	No
count	number	The number of results to return.	No

Output

The result of the expansion in ValueSet form. The contents of the expansion are in the ValueSet.expansion property.

Examples

Query all values for a ValueSet:

curl 'https://api.medplum.com/fhir/R4/ValueSet/$expand?url=http%3A%2F%2Fhl7.org%2Ffhir%2FValueSet%2Fadministrative-gender' \
  -H "Content-Type: application/fhir+json" \
  -H "Authorization: Bearer MY_ACCESS_TOKEN"

{
  "resourceType": "ValueSet",
  "url": "http://hl7.org/fhir/ValueSet/administrative-gender",
  "expansion": {
    "offset": 0,
    "contains": [
      {
        "system": "http://hl7.org/fhir/administrative-gender",
        "code": "female",
        "display": "Female"
      },
      {
        "system": "http://hl7.org/fhir/administrative-gender",
        "code": "male",
        "display": "Male"
      },
      {
        "system": "http://hl7.org/fhir/administrative-gender",
        "code": "other",
        "display": "Other"
      },
      {
        "system": "http://hl7.org/fhir/administrative-gender",
        "code": "unknown",
        "display": "Unknown"
      }
    ]
  }
}

Filter by search string:

curl 'https://api.medplum.com/fhir/R4/ValueSet/$expand?url=http%3A%2F%2Fhl7.org%2Ffhir%2FValueSet%2Fadministrative-gender&filter=f' \
  -H "Content-Type: application/fhir+json" \
  -H "Authorization: Bearer MY_ACCESS_TOKEN"

{
  "resourceType": "ValueSet",
  "url": "http://hl7.org/fhir/ValueSet/administrative-gender",
  "expansion": {
    "offset": 0,
    "contains": [
      {
        "system": "http://hl7.org/fhir/administrative-gender",
        "code": "female",
        "display": "Female"
      }
    ]
  }
}

The MedplumClient TypeScript class provides a searchValueSet convenience method:

const url = 'http://hl7.org/fhir/ValueSet/administrative-gender';
const input = 'f';
const result = await medplum.searchValueSet(url, input);