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Version: v0.1.13

Read Bundles and resolve references

A Bundle is read like any other resource, with parseResource or parseResourceXml. These helpers read what the Bundle says about its entries and resolve the references between them. None of them executes anything: a transaction is described, never applied.

Tell a transaction from a batch​

readBundle reports the Bundle's type, the processing that type implies, and one entry per Bundle.entry. atomic is true only for a transaction, whose entries succeed or fail together; a batch is independent, each entry on its own:

import { parseResource, readBundle } from "@cosyte/fhir";

const transaction = readBundle(
  parseResource(
    '{"resourceType":"Bundle","type":"transaction","entry":[{"fullUrl":"urn:uuid:a1b2c3d4-e5f6-4a7b-8c9d-e0f1a2b3c4d5","resource":{"resourceType":"Patient","id":"syn-0001"},"request":{"method":"POST","url":"Patient"}}]}',
  ).resource,
);

transaction.atomic; // => true
transaction.processing; // => "atomic"
transaction.entries.map((entry) => [entry.resourceType, entry.requestMethod, entry.requestUrl]); // => [["Patient", "POST", "Patient"]]

const batch = readBundle(parseResource('{"resourceType":"Bundle","type":"batch"}').resource);

batch.atomic; // => false
batch.processing; // => "independent"

A Bundle with no type, or an entry missing its parts, still reads: the missing values come back undefined rather than throwing, so the shape of what arrived is visible.

Resolve a reference inside a Bundle​

buildBundleIndex keys every entry by its fullUrl and, where it can be derived, by Type/id, so a relative, absolute or logical reference can find it. resolveReference then answers one of three ways:

  • resolved, with the target resource, when the reference names an entry in the Bundle;
  • unresolved, when a relative reference names a resource the Bundle does not carry;
  • external, when an absolute reference points outside the Bundle, which is not a defect.
import { buildBundleIndex, parseResource, resolveReference } from "@cosyte/fhir";

const { resource } = parseResource(
  '{"resourceType":"Bundle","type":"collection","entry":[{"fullUrl":"https://fhir.example.org/Patient/syn-0001","resource":{"resourceType":"Patient","id":"syn-0001","managingOrganization":{"reference":"Organization/syn-org-1"}}}]}',
);

const index = buildBundleIndex(resource);

resolveReference("Patient/syn-0001", { bundle: index }).status; // => "resolved"
resolveReference("https://fhir.example.org/Patient/syn-0001", { bundle: index }).status; // => "resolved"
resolveReference("Organization/syn-org-1", { bundle: index }).status; // => "unresolved"
resolveReference("https://other.example.org/fhir/Patient/9", { bundle: index }).status; // => "external"

validateResource reports the same unresolved reference on the Bundle, by location and never by value, at warning severity:

import { parseResource, validateResource } from "@cosyte/fhir";

const { resource } = parseResource(
  '{"resourceType":"Bundle","type":"collection","entry":[{"fullUrl":"https://fhir.example.org/Patient/syn-0001","resource":{"resourceType":"Patient","id":"syn-0001","managingOrganization":{"reference":"Organization/syn-org-1"}}}]}',
);

const unresolved = validateResource(resource).issues.filter(
  (issue) => issue.code === "REFERENCE_UNRESOLVED",
);

unresolved.map((issue) => [issue.severity, issue.expression]); // => [["warning", "Bundle.entry[0].resource.managingOrganization.reference"]]

Resolve a reference to a contained resource​

A #fragment reference resolves only among the resource's own contained resources. Index them with containedIndex and pass that instead of a Bundle index:

import { containedIndex, parseResource, resolveReference } from "@cosyte/fhir";

const { resource } = parseResource(
  '{"resourceType":"Observation","status":"final","code":{"text":"synthetic"},"contained":[{"resourceType":"Patient","id":"p1"}],"subject":{"reference":"#p1"}}',
);

const contained = containedIndex(resource);

resolveReference("#p1", { contained }).status; // => "resolved"
resolveReference("#p2", { contained }).status; // => "unresolved"

Reference​