fix: iterator response length

hypermedia-app · Jul 8, 2021 · acf324d · acf324d
1 parent a15434d
commit acf324d
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Showing 3 changed files with 38 additions and 11 deletions.
diff --git a/.changeset/silent-peas-fold.md b/.changeset/silent-peas-fold.md
@@ -2,4 +2,4 @@
 "alcaeus": patch
 ---
 
-Iterating response would return same resource multiple times
+Iterating response and resource count would return same resource multiple times
diff --git a/src/ResourceRepresentation.ts b/src/ResourceRepresentation.ts
@@ -37,11 +37,31 @@ export default class <D extends DatasetCore, T extends RdfResourceCore<D>> imple
     private __graph: AnyPointer<AnyContext, D>
     private __factory: ResourceFactory
     private readonly rootNode: GraphPointer<ResourceIdentifier>
+    private __uniqueResources: () => Map<Term, Hydra.Resource<D>>
 
     public constructor(graph: AnyPointer<AnyContext, D>, factory: ResourceFactory, rootResource: NamedNode) {
         this.__graph = graph
         this.__factory = factory
         this.rootNode = graph.node(rootResource)
+
+        this.__uniqueResources = (() => {
+            let map: Map<Term, Hydra.Resource<D>>
+
+            return () => {
+                if (!map) {
+                    map = this.__graph.in().toArray()
+                        .reduce((uniq, pointer) => {
+                            if (!uniq.has(pointer.term)) {
+                                return uniq.set(pointer.term, this._createEntity(pointer))
+                            }
+
+                            return uniq
+                        }, new TermMap<Term, Hydra.Resource<D>>())
+                }
+
+                return map
+            }
+        })()
     }
 
     public get<T>(uri: string): (T & Hydra.Resource<D>) | undefined {
@@ -64,7 +84,7 @@ export default class <D extends DatasetCore, T extends RdfResourceCore<D>> imple
     }
 
     public get length(): number {
-        return this.__graph.in().terms.length
+        return this.__uniqueResources().size
     }
 
     public ofType<T>(classId: string | NamedNode) {
@@ -74,15 +94,7 @@ export default class <D extends DatasetCore, T extends RdfResourceCore<D>> imple
     }
 
     public [Symbol.iterator]() {
-        return this.__graph.in().toArray()
-            .reduce((uniq, pointer) => {
-                if (!uniq.has(pointer.term)) {
-                    return uniq.set(pointer.term, this._createEntity(pointer))
-                }
-
-                return uniq
-            }, new TermMap<Term, Hydra.Resource<D>>())
-            .values()
+        return this.__uniqueResources().values()
     }
 
     private _createEntity<T>(node: GraphPointer<ResourceIdentifier>) {

diff --git a/tests/ResourceRepresentation-spec.ts b/tests/ResourceRepresentation-spec.ts
@@ -49,6 +49,21 @@ describe('ResourceRepresentation', () => {
         )
     })
 
+    describe('length', () => {
+        it('should count unique resources', () => {
+            // given
+            const dataset = $rdf.dataset()
+            cf({ dataset, graph: ex.a })
+                .namedNode(ex.a).addOut(rdf.type, ex.Res).addOut(schema.knows, [ex.b, ex.c, ex.d])
+                .namedNode(ex.c).addOut(schema.knows, [ex.a, ex.d])
+                .namedNode(ex.d).addIn(schema.knows, ex.a)
+            const r12n = new ResourceRepresentation(cf({ dataset, graph: ex.a }), factory, ex.a)
+
+            // then
+            expect(r12n.length).toEqual(2)
+        })
+    })
+
     describe('root', () => {
         it('should use selection root resource as specified by parameter', () => {
             // given