feat(core): add Store.findMembers

Author: jg10-mastodon-social

core/src/Store.spec.ts

@@ -1,5 +1,5 @@
 import { when } from "jest-when";
-import { sym } from "rdflib";
+import { quad, sym } from "rdflib";
 import { Parser as SparqlParser, Update } from "sparqljs";
 import { AuthenticatedFetch, PodOsSession } from "./authentication";
 import { Store } from "./Store";
@@ -450,6 +450,32 @@ describe("Store", () => {
       );
     });
   });
+
+  describe("findMembers", () => {
+    it("finds instances of classes and subclasses", () => {
+      const store = new Store({} as PodOsSession);
+      store.graph.addAll([
+        quad(
+          sym("http://recipe.test/1"),
+          sym("http://www.w3.org/1999/02/22-rdf-syntax-ns#type"),
+          sym("http://schema.org/Recipe"),
+        ),
+        quad(
+          sym("http://recipe.test/RecipeClass"),
+          sym("http://www.w3.org/2000/01/rdf-schema#subClassOf"),
+          sym("http://schema.org/Recipe"),
+        ),
+        quad(
+          sym("http://recipe.test/2"),
+          sym("http://www.w3.org/1999/02/22-rdf-syntax-ns#type"),
+          sym("http://recipe.test/RecipeClass"),
+        ),
+      ]);
+      const members = store.findMembers("http://schema.org/Recipe");
+      expect(members).toContain("http://recipe.test/1");
+      expect(members).toContain("http://recipe.test/2");
+    });
+  });
 });
 
 export function thenSparqlUpdateIsSentToUrl(

core/src/Store.ts

@@ -133,4 +133,12 @@ export class Store {
   async executeUpdate(operation: UpdateOperation) {
     await executeUpdate(this.fetcher, this.updater, operation);
   }
+
+  /**
+   * Finds instances of the given class or its sub-classes
+   * @param classUri
+   */
+  findMembers(classUri: string): string[] {
+    return Object.keys(this.graph.findMemberURIs(sym(classUri)));
+  }
 }