fix: Avoid including undefined bodies in DELETE

src/useMutate.test.tsx

@@ -148,6 +148,26 @@ describe("useMutate", () => {
       expect(res).toEqual({ id: 1 });
     });
 
+    it("should deal with undefined bodies", async () => {
+      nock("https://my-awesome-api.fake")
+        .delete("/")
+        .reply(200, { id: 1 });
+
+      const wrapper: React.FC = ({ children }) => (
+        <RestfulProvider base="https://my-awesome-api.fake">{children}</RestfulProvider>
+      );
+      const { result } = renderHook(() => useMutate<any, any, { [key: string]: any }, void, void>("DELETE", ""), {
+        wrapper,
+      });
+      const res = await result.current.mutate();
+
+      expect(result.current).toMatchObject({
+        error: null,
+        loading: false,
+      });
+      expect(res).toEqual({ id: 1 });
+    });
+
     it("should deal with query parameters", async () => {
       nock("https://my-awesome-api.fake")
         .delete("/")

src/useMutate.tsx

@@ -122,7 +122,7 @@ export function useMutate<
         options.body = body;
       } else if (typeof body === "object") {
         options.body = JSON.stringify(body);
-      } else if (isDelete) {
+      } else if (isDelete && body !== undefined) {
         const possiblyEncodedBody = props.pathInlineBodyEncode
           ? props.pathInlineBodyEncode(String(body))
           : String(body);