BREAKING CHANGE: update dataset wrapper

README.md

@@ -91,7 +91,7 @@ For example, you can write a `People` dataset wrapper to find each `Person` in a
 ```javascript
 class People extends DatasetWrapper {
 	[Symbol.iterator]() {
-		return this.subjectsOf("http://example.com/name", Person)
+		return this.subjectsOf(Person, "http://example.com/name")
 	}
 }
 ```

src/DatasetWrapper.ts

@@ -4,30 +4,14 @@ import type { DataFactory, DatasetCore, Term } from "@rdfjs/types"
 type TermWrapperConstructor<T> = new (term: Term, dataset: DatasetCore, factory: DataFactory) => T
 
 export class DatasetWrapper extends DatasetCoreBase {
-    protected subjectsOf<T>(predicate: string, termWrapper: TermWrapperConstructor<T>): Iterable<T> {
-        return this.matchSubjectsOf(termWrapper, predicate)
-    }
-
-    protected* matchSubjectsOf<T>(termWrapper: TermWrapperConstructor<T>, predicate?: string, object?: string, graph?: string): Iterable<T> {
-        const p = predicate ? this.factory.namedNode(predicate) : undefined
-        const o = object ? this.factory.namedNode(object) : undefined
-        const g = graph ? this.factory.namedNode(graph) : undefined
-
-        for (const q of this.match(undefined, p, o, g)) {
+    protected* subjectsOf<T>(termWrapper: TermWrapperConstructor<T>, predicate?: string, object?: string | Term, graph?: string): Iterable<T> {
+        for (const q of this.match(undefined, toTerm(predicate, this.factory), toTerm(object, this.factory), toTerm(graph, this.factory))) {
             yield new termWrapper(q.subject, this, this.factory)
         }
     }
 
-    protected* objectsOf<T>(predicate: string, termWrapper: TermWrapperConstructor<T>): Iterable<T> {
-        return this.matchObjectsOf(termWrapper, undefined, predicate)
-    }
-
-    protected* matchObjectsOf<T>(termWrapper: TermWrapperConstructor<T>, subject?: string, predicate?: string, graph?: string): Iterable<T> {
-        const s = subject ? this.factory.namedNode(subject) : undefined
-        const p = predicate ? this.factory.namedNode(predicate) : undefined
-        const g = graph ? this.factory.namedNode(graph) : undefined
-
-        for (const q of this.match(s, p, undefined, g)) {
+    protected* objectsOf<T>(termWrapper: TermWrapperConstructor<T>, predicate?: string, subject?: string | Term, graph?: string): Iterable<T> {
+        for (const q of this.match(toTerm(subject, this.factory), toTerm(predicate, this.factory), undefined, toTerm(graph, this.factory))) {
             yield new termWrapper(q.object, this, this.factory)
         }
     }
@@ -36,6 +20,10 @@ export class DatasetWrapper extends DatasetCoreBase {
         // TODO: Vocab
         const rdfType = "http://www.w3.org/1999/02/22-rdf-syntax-ns#type"
 
-        return this.matchSubjectsOf(constructor, rdfType, classTerm)
+        return this.subjectsOf(constructor, rdfType, classTerm)
     }
 }
+
+function toTerm(value: string | Term | undefined, factory: DataFactory): Term | undefined {
+    return typeof value === "string" ? factory.namedNode(value) : value
+}

test/unit/model/ParentDataset.ts

@@ -4,6 +4,6 @@ import { Vocabulary } from "../Vocabulary.js"
 
 export class ParentDataset extends DatasetWrapper {
     public get subjectsOfHasChild(): Iterable<Parent> {
-        return this.subjectsOf(Vocabulary.hasChild, Parent)
+        return this.subjectsOf(Parent, Vocabulary.hasChild)
     }
 }