From 3309850063943bfca50738596ced1fe06a30675c Mon Sep 17 00:00:00 2001
From: Nicolas Ayral Seydoux <nseydoux@inrupt.com>
Date: Wed, 18 Dec 2024 14:28:00 +0100
Subject: [PATCH] Add async iterator for query results

---
 e2e/node/e2e.test.ts        | 15 +++++++++++++++
 src/gConsent/index.ts       |  1 +
 src/gConsent/query/query.ts | 19 +++++++++++++++++++
 src/index.ts                |  1 +
 4 files changed, 36 insertions(+)

diff --git a/e2e/node/e2e.test.ts b/e2e/node/e2e.test.ts
index 0eaf187d..6b4708c2 100644
--- a/e2e/node/e2e.test.ts
+++ b/e2e/node/e2e.test.ts
@@ -87,6 +87,7 @@ import {
   getPurposes,
 } from "../../src/common/getters";
 import { toBeEqual } from "../../src/gConsent/util/toBeEqual.mock";
+import { paginateQuery } from "../../src/gConsent/query/query";
 
 const { namedNode } = DataFactory;
 
@@ -1768,4 +1769,18 @@ describe(`End-to-end access grant tests for environment [${environment}] `, () =
       );
     });
   });
+
+  it.only("can iterate through pages", async () => {
+    const pages = paginateQuery(
+      {},
+      {
+        fetch: addUserAgent(requestorSession.fetch, TEST_USER_AGENT),
+        // FIXME add query endpoint discovery check.
+        queryEndpoint: new URL("query", vcProvider),
+      },
+    );
+    for await (const page of pages) {
+      expect(page.items).not.toHaveLength(0);
+    }
+  });
 });
diff --git a/src/gConsent/index.ts b/src/gConsent/index.ts
index c02b5f3e..26b19de7 100644
--- a/src/gConsent/index.ts
+++ b/src/gConsent/index.ts
@@ -52,6 +52,7 @@ export {
   CredentialType,
   DURATION,
   query,
+  paginateQuery,
 } from "./query/query";
 
 export {
diff --git a/src/gConsent/query/query.ts b/src/gConsent/query/query.ts
index cb87fd3a..25803848 100644
--- a/src/gConsent/query/query.ts
+++ b/src/gConsent/query/query.ts
@@ -260,3 +260,22 @@ export async function query(
   }
   return toCredentialResult(response);
 }
+
+export async function* paginateQuery(
+  filter: CredentialFilter,
+  options: {
+    fetch: typeof fetch;
+    queryEndpoint: URL;
+  },
+) {
+  let page = await query(filter, options);
+  while (page.next !== undefined) {
+    yield page;
+    // This is a generator, so we don't want to go through
+    // all the pages at once with a Promise.all approach.
+    // eslint-disable-next-line no-await-in-loop
+    page = await query(page.next, options);
+  }
+  // Return the last page.
+  yield page;
+}
diff --git a/src/index.ts b/src/index.ts
index a1d0d1bc..646e714f 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -60,6 +60,7 @@ export {
   getAccessManagementUi,
   getAccessRequestFromRedirectUrl,
   issueAccessRequest,
+  paginateQuery,
   query,
   redirectToAccessManagementUi,
   redirectToRequestor,