Fix listFederation, add id property (#67 option 1)

If coming from a spec-compliant backend, `this.data.federation` is an object, so the function used to always return the empty array. The code now transforms the object into an array, and also adds the former object keys to each item as an `id` property.

Author: christophfriedrich

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `id` field to the objects in the array returned by `listFederation` in `Capabilities`
+
 ## [2.7.0] - 2025-01-04
 
 ### Added

src/capabilities.js

@@ -198,7 +198,15 @@ class Capabilities {
 	 * @returns {Array.<FederationBackend>} Array of backends
 	 */
 	listFederation() {
-		return Array.isArray(this.data.federation) ? this.data.federation : [];
+		let federation = [];
+		if (Utils.isObject(this.data.federation)) {
+			// convert to array and add keys as `id` property
+			for(const [key, backend] of Object.entries(this.data.federation)) {
+				backend.id = key;
+				federation.push(backend);
+			}
+		}
+		return federation;
 	}
 
 	/**

src/typedefs.js

@@ -200,6 +200,7 @@
  * 
  * @typedef FederationBackend
  * @type {object}
+ * @property {string} id ID of the back-end within the federation.
  * @property {string} url URL to the versioned API endpoint of the back-end.
  * @property {string} title Name of the back-end.
  * @property {string} description A description of the back-end and its specifics.