fix: handle null in isJSONSerializable to prevent TypeError

src/utils.ts

@@ -15,11 +15,11 @@ export function isPayloadMethod(method = "GET"): boolean {
 }
 
 export function isJSONSerializable(value: any): boolean {
-  if (value === undefined) {
+  if (value === undefined || value === null) {
     return false;
   }
   const t = typeof value;
-  if (t === "string" || t === "number" || t === "boolean" || t === null) {
+  if (t === "string" || t === "number" || t === "boolean") {
     return true;
   }
   if (t !== "object") {

test/index.test.ts

@@ -525,3 +525,46 @@ describe("ofetch", () => {
     });
   });
 });
+
+describe("isJSONSerializable", () => {
+  let isJSONSerializable: any;
+
+  beforeAll(async () => {
+    const utils = await import("../src/utils.ts");
+    isJSONSerializable = utils.isJSONSerializable;
+  });
+
+  it("returns false for null", () => {
+    expect(isJSONSerializable(null)).toBe(false); // eslint-disable-line unicorn/no-null
+  });
+
+  it("returns false for undefined", () => {
+    expect(isJSONSerializable(undefined)).toBe(false);
+  });
+
+  it("returns true for primitive types", () => {
+    expect(isJSONSerializable("string")).toBe(true);
+    expect(isJSONSerializable(123)).toBe(true);
+    expect(isJSONSerializable(true)).toBe(true);
+    expect(isJSONSerializable(false)).toBe(true);
+  });
+
+  it("returns true for plain objects and arrays", () => {
+    expect(isJSONSerializable({})).toBe(true);
+    expect(isJSONSerializable([])).toBe(true);
+    expect(isJSONSerializable({ a: 1 })).toBe(true);
+  });
+
+  it("returns false for TypedArray (has .buffer property)", () => {
+    expect(isJSONSerializable(new Uint8Array(10))).toBe(false);
+  });
+
+  it("returns false for ArrayBuffer", () => {
+    expect(isJSONSerializable(new ArrayBuffer(10))).toBe(false);
+  });
+
+  it("returns false for FormData and URLSearchParams", () => {
+    expect(isJSONSerializable(new FormData())).toBe(false);
+    expect(isJSONSerializable(new URLSearchParams())).toBe(false);
+  });
+});