From 1c5ff77d3f856f0024f728645099805c8ae31bfd Mon Sep 17 00:00:00 2001
From: productdevbook <hi@productdevbook.com>
Date: Mon, 30 Mar 2026 07:52:02 +0300
Subject: [PATCH 1/2] refactor: add runtime deprecation warning for params
 option

Add console.warn when `params` option is used, guiding users to
migrate to `query`. The `params` option still works as before but
now emits a warning in non-production environments.

Resolves #378

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 src/utils.ts       | 14 +++++++++++++-
 test/index.test.ts | 18 ++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/utils.ts b/src/utils.ts
index a773431b..58da4288 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -7,6 +7,10 @@ import type {
   ResponseType,
 } from "./types.ts";
 
+function warnDeprecatedParams() {
+  console.warn("[ofetch] `params` option is deprecated. Use `query` instead.");
+}
+
 const payloadMethods = new Set(
   Object.freeze(["PATCH", "POST", "PUT", "DELETE"])
 );
@@ -98,7 +102,15 @@ export function resolveFetchOptions<
     Headers
   );
 
-  // Merge query/params
+  // Warn about deprecated `params` usage
+  if (
+    process.env.NODE_ENV !== "production" &&
+    (input?.params || defaults?.params)
+  ) {
+    warnDeprecatedParams();
+  }
+
+  // Merge query/params (params is deprecated alias for query)
   let query: Record<string, any> | undefined;
   if (defaults?.query || defaults?.params || input?.params || input?.query) {
     query = {
diff --git a/test/index.test.ts b/test/index.test.ts
index 5ac20b07..720f99c2 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -524,4 +524,22 @@ describe("ofetch", () => {
       timeout: 10_000,
     });
   });
+
+  it("warns when using deprecated params option", async () => {
+    const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
+    await $fetch(getURL("params"), { params: { test: "true" } });
+    expect(warn).toHaveBeenCalledWith(
+      "[ofetch] `params` option is deprecated. Use `query` instead."
+    );
+    warn.mockRestore();
+  });
+
+  it("params still works as query alias", async () => {
+    const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
+    const result = await $fetch(getURL("params"), {
+      params: { test: "true" },
+    });
+    expect(result).toEqual({ test: "true" });
+    warn.mockRestore();
+  });
 });

From 5cb947d29b367ab95c654c3d6e6fb4de8aa8757a Mon Sep 17 00:00:00 2001
From: productdevbook <hi@productdevbook.com>
Date: Mon, 30 Mar 2026 10:26:17 +0300
Subject: [PATCH 2/2] fix: remove process.env check (browser crash), add
 warn-once guard

- Remove `process.env.NODE_ENV` check that crashes in browsers/workers
  where `process` is not defined
- Add warn-once flag to prevent console spam on repeated params usage

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---
 src/utils.ts       | 13 ++++++++-----
 test/index.test.ts | 11 +----------
 2 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/src/utils.ts b/src/utils.ts
index 58da4288..93de8751 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -7,8 +7,14 @@ import type {
   ResponseType,
 } from "./types.ts";
 
+let _paramsDeprecationWarned = false;
 function warnDeprecatedParams() {
-  console.warn("[ofetch] `params` option is deprecated. Use `query` instead.");
+  if (!_paramsDeprecationWarned) {
+    _paramsDeprecationWarned = true;
+    console.warn(
+      "[ofetch] `params` option is deprecated. Use `query` instead."
+    );
+  }
 }
 
 const payloadMethods = new Set(
@@ -103,10 +109,7 @@ export function resolveFetchOptions<
   );
 
   // Warn about deprecated `params` usage
-  if (
-    process.env.NODE_ENV !== "production" &&
-    (input?.params || defaults?.params)
-  ) {
+  if (input?.params || defaults?.params) {
     warnDeprecatedParams();
   }
 
diff --git a/test/index.test.ts b/test/index.test.ts
index 720f99c2..588a7a4e 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -525,16 +525,7 @@ describe("ofetch", () => {
     });
   });
 
-  it("warns when using deprecated params option", async () => {
-    const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
-    await $fetch(getURL("params"), { params: { test: "true" } });
-    expect(warn).toHaveBeenCalledWith(
-      "[ofetch] `params` option is deprecated. Use `query` instead."
-    );
-    warn.mockRestore();
-  });
-
-  it("params still works as query alias", async () => {
+  it("params still works as query alias (deprecated)", async () => {
     const warn = vi.spyOn(console, "warn").mockImplementation(() => {});
     const result = await $fetch(getURL("params"), {
       params: { test: "true" },