From 4f9d2f3d0f9ab5950ee977970a0e5e590b4cbc2f Mon Sep 17 00:00:00 2001
From: Blake Szabo <blake.szabo@gmail.com>
Date: Wed, 2 Oct 2024 09:38:12 +1000
Subject: [PATCH] fix(openapi-fetch): Prevent orphan ampersands in query from
 empty arrays

---
 .changeset/strong-boats-drive.md                |  5 +++++
 packages/openapi-fetch/src/index.js             |  3 +++
 .../openapi-fetch/test/common/params.test.ts    | 17 +++++++++++++++++
 3 files changed, 25 insertions(+)
 create mode 100644 .changeset/strong-boats-drive.md

diff --git a/.changeset/strong-boats-drive.md b/.changeset/strong-boats-drive.md
new file mode 100644
index 000000000..a5275e3d2
--- /dev/null
+++ b/.changeset/strong-boats-drive.md
@@ -0,0 +1,5 @@
+---
+"openapi-fetch": patch
+---
+
+Fix multiple empty arrays in query params appending extra ampersands
diff --git a/packages/openapi-fetch/src/index.js b/packages/openapi-fetch/src/index.js
index 56c4826d5..17726464a 100644
--- a/packages/openapi-fetch/src/index.js
+++ b/packages/openapi-fetch/src/index.js
@@ -436,6 +436,9 @@ export function createQuerySerializer(options) {
           continue;
         }
         if (Array.isArray(value)) {
+          if (value.length === 0) {
+            continue;
+          }
           search.push(
             serializeArrayParam(name, value, {
               style: "form",
diff --git a/packages/openapi-fetch/test/common/params.test.ts b/packages/openapi-fetch/test/common/params.test.ts
index 623101dfb..67a322bf6 100644
--- a/packages/openapi-fetch/test/common/params.test.ts
+++ b/packages/openapi-fetch/test/common/params.test.ts
@@ -264,6 +264,23 @@ describe("params", () => {
         expect(actualURL.search).toBe("");
       });
 
+      test("array params (empty, multiple)", async () => {
+        let actualURL = new URL("https://fakeurl.example");
+        const client = createObservedClient<paths>({}, async (req) => {
+          actualURL = new URL(req.url);
+          return Response.json({});
+        });
+
+        await client.GET("/query-params", {
+          params: {
+            query: { array: [], second_array: [], third_array: [] },
+          },
+        });
+
+        expect(actualURL.pathname).toBe("/query-params");
+        expect(actualURL.search).toBe("");
+      });
+
       test("empty/null params", async () => {
         let actualURL = new URL("https://fakeurl.example");
         const client = createObservedClient<paths>({}, async (req) => {