Add iteroator unit tests

src/gConsent/query/query.test.ts

@@ -20,8 +20,8 @@
 //
 
 import { jest, it, describe, expect } from "@jest/globals";
-import type { CredentialFilter } from "./query";
-import { DURATION, query } from "./query";
+import type { CredentialFilter, CredentialResult } from "./query";
+import { DURATION, paginatedQuery, query } from "./query";
 import { mockAccessGrantVc } from "../util/access.mock";
 
 describe("query", () => {
@@ -205,3 +205,74 @@ describe("query", () => {
     ).rejects.toThrow();
   });
 });
+
+describe("paginatedQuery", () => {
+  it("follows the pagination links", async () => {
+    const nextQueryParams = {
+      type: "SolidAccessGrant",
+      page: "6af7d740",
+      status: "Active",
+    };
+    const linkNext = `<https://vc.example.org/query?${new URLSearchParams(nextQueryParams)}>; rel="next"`;
+    const paginationHeaders = new Headers();
+    paginationHeaders.append("Link", linkNext);
+    const mockedGrant = await mockAccessGrantVc();
+    const pages: CredentialResult[] = [];
+    const mockedFetch = jest
+      .fn<typeof fetch>()
+      .mockResolvedValueOnce(
+        new Response(
+          JSON.stringify({
+            items: [mockedGrant],
+          }),
+          {
+            headers: paginationHeaders,
+          },
+        ),
+      )
+      .mockResolvedValueOnce(
+        new Response(
+          JSON.stringify({
+            items: [mockedGrant],
+          }),
+          // The second response has no pagination headers to complete iteration.
+        ),
+      );
+
+    for await (const page of paginatedQuery(
+      {},
+      {
+        queryEndpoint: new URL("https://vc.example.org/query"),
+        fetch: mockedFetch,
+      },
+    )) {
+      expect(page.items).toHaveLength(1);
+      pages.push(page);
+    }
+    expect(pages).toHaveLength(2);
+  });
+
+  it("supports results not having a next page", async () => {
+    const mockedGrant = await mockAccessGrantVc();
+    const pages: CredentialResult[] = [];
+    const mockedFetch = jest.fn<typeof fetch>().mockResolvedValueOnce(
+      new Response(
+        JSON.stringify({
+          items: [mockedGrant],
+        }),
+      ),
+    );
+
+    for await (const page of paginatedQuery(
+      {},
+      {
+        queryEndpoint: new URL("https://vc.example.org/query"),
+        fetch: mockedFetch,
+      },
+    )) {
+      expect(page.items).toHaveLength(1);
+      pages.push(page);
+    }
+    expect(pages).toHaveLength(1);
+  });
+});

src/gConsent/query/query.ts

@@ -216,7 +216,8 @@ function toQueryUrl(endpoint: URL, filter: CredentialFilter): URL {
 }
 
 /**
- * Query for Access Credentials (Access Requests, Access Grants or Access Denials) based on a given filter.
+ * Query for Access Credential (Access Requests, Access Grants or Access Denials) based on a given filter,
+ * and get a page of results.
  *
  * @param filter The query filter
  * @param options Query options
@@ -266,7 +267,30 @@ export async function query(
   return toCredentialResult(response);
 }
 
-export async function* paginateQuery(
+/**
+ * Query for Access Credential (Access Requests, Access Grants or Access Denials) based on a given filter,
+ * and traverses all of the result pages.
+ *
+ * @param filter The query filter
+ * @param options Query options
+ * @returns an async iterator going through the result pages
+ * @since unreleased
+ *
+ * @example
+ * ```
+ *  const pages = paginatedQuery(
+ *     {},
+ *     {
+ *       fetch: session.fetch,
+ *       queryEndpoint: new URL("https://vc.example.org/query"),
+ *     },
+ *   );
+ *   for await (const page of pages) {
+ *     // do something with the result page.
+ *   }
+ * ```
+ */
+export async function* paginatedQuery(
   filter: CredentialFilter,
   options: {
     fetch: typeof fetch;
@@ -282,5 +306,5 @@ export async function* paginateQuery(
     page = await query(page.next, options);
   }
   // Return the last page.
-  return page;
+  yield page;
 }