diff --git a/docs/.vitepress/theme/index.ts b/docs/.vitepress/theme/index.ts
index 569e62b..027ca3d 100644
--- a/docs/.vitepress/theme/index.ts
+++ b/docs/.vitepress/theme/index.ts
@@ -1,5 +1,5 @@
-import DefaultTheme from "vitepress/theme";
 import type { Theme } from "vitepress";
+import DefaultTheme from "vitepress/theme";
 import "./custom.css";
 
 const theme: Theme = {
diff --git a/packages/core/src/adapters/download.ts b/packages/core/src/adapters/download.ts
index 3bc51eb..131ae1e 100644
--- a/packages/core/src/adapters/download.ts
+++ b/packages/core/src/adapters/download.ts
@@ -1,9 +1,9 @@
 import statuses from "statuses";
-import { settle } from "../core/settle";
+import type { UnCancelTokenListener } from "../core/UnCancelToken";
 import { UnCanceledError } from "../core/UnCanceledError";
+import { settle } from "../core/settle";
+import type { UnConfig, UnData, UnResponse } from "../types";
 import { buildDownloadConfig } from "../utils";
-import { UnCancelTokenListener } from "../core/UnCancelToken";
-import type { UnData, UnConfig, UnResponse } from "../types";
 
 export const downloadAdapter = <T = UnData, D = UnData>(
   config: UnConfig<T, D>,
@@ -102,8 +102,8 @@ export const downloadAdapter = <T = UnData, D = UnData>(
         if (!task) {
           return;
         }
-        // @ts-expect-error no types
         reject(
+          // @ts-expect-error type not existed
           !cancel || cancel.type
             ? new UnCanceledError(undefined, config, task)
             : cancel,
@@ -113,9 +113,8 @@ export const downloadAdapter = <T = UnData, D = UnData>(
       };
 
       cancelToken?.subscribe(onCanceled);
-      // @ts-expect-error no types
       signal?.aborted
-        ? onCanceled()
-        : signal?.addEventListener("abort", onCanceled);
+        ? onCanceled({})
+        : signal?.addEventListener?.("abort", onCanceled);
     }
   });
diff --git a/packages/core/src/adapters/request.ts b/packages/core/src/adapters/request.ts
index 3b58c03..d5941a1 100644
--- a/packages/core/src/adapters/request.ts
+++ b/packages/core/src/adapters/request.ts
@@ -1,9 +1,9 @@
 import statuses from "statuses";
-import { settle } from "../core/settle";
+import type { UnCancelTokenListener } from "../core/UnCancelToken";
 import { UnCanceledError } from "../core/UnCanceledError";
+import { settle } from "../core/settle";
+import type { UnConfig, UnData, UnResponse } from "../types";
 import { buildRequestConfig } from "../utils";
-import { UnCancelTokenListener } from "../core/UnCancelToken";
-import type { UnData, UnConfig, UnResponse } from "../types";
 
 export const requestAdapter = <T = UnData, D = UnData>(
   config: UnConfig<T, D>,
@@ -95,8 +95,8 @@ export const requestAdapter = <T = UnData, D = UnData>(
         if (!task) {
           return;
         }
-        // @ts-expect-error no types
         reject(
+          // @ts-expect-error type not existed
           !cancel || cancel.type
             ? new UnCanceledError(undefined, config, task)
             : cancel,
@@ -106,9 +106,8 @@ export const requestAdapter = <T = UnData, D = UnData>(
       };
 
       cancelToken?.subscribe(onCanceled);
-      // @ts-expect-error no types
       signal?.aborted
-        ? onCanceled()
-        : signal?.addEventListener("abort", onCanceled);
+        ? onCanceled({})
+        : signal?.addEventListener?.("abort", onCanceled);
     }
   });
diff --git a/packages/core/src/adapters/upload.ts b/packages/core/src/adapters/upload.ts
index 3ff90ab..d0d6c8a 100644
--- a/packages/core/src/adapters/upload.ts
+++ b/packages/core/src/adapters/upload.ts
@@ -1,9 +1,9 @@
 import statuses from "statuses";
-import { settle } from "../core/settle";
+import type { UnCancelTokenListener } from "../core/UnCancelToken";
 import { UnCanceledError } from "../core/UnCanceledError";
+import { settle } from "../core/settle";
+import type { UnConfig, UnData, UnResponse } from "../types";
 import { buildUploadConfig } from "../utils";
-import { UnCancelTokenListener } from "../core/UnCancelToken";
-import type { UnData, UnConfig, UnResponse } from "../types";
 
 export const uploadAdapter = <T = UnData, D = UnData>(config: UnConfig<T, D>) =>
   new Promise<UnResponse<T, D>>((resolve, reject) => {
@@ -96,8 +96,8 @@ export const uploadAdapter = <T = UnData, D = UnData>(config: UnConfig<T, D>) =>
         if (!task) {
           return;
         }
-        // @ts-expect-error no types
         reject(
+          // @ts-expect-error type not existed
           !cancel || cancel.type
             ? new UnCanceledError(undefined, config, task)
             : cancel,
@@ -107,9 +107,8 @@ export const uploadAdapter = <T = UnData, D = UnData>(config: UnConfig<T, D>) =>
       };
 
       cancelToken?.subscribe(onCanceled);
-      // @ts-expect-error no types
       signal?.aborted
-        ? onCanceled()
-        : signal?.addEventListener("abort", onCanceled);
+        ? onCanceled({})
+        : signal?.addEventListener?.("abort", onCanceled);
     }
   });
diff --git a/packages/core/src/composables.ts b/packages/core/src/composables.ts
index 27b2112..38832e2 100644
--- a/packages/core/src/composables.ts
+++ b/packages/core/src/composables.ts
@@ -1,14 +1,14 @@
+import { noop, until } from "@vueuse/core";
 import type { Ref, ShallowRef } from "vue-demi";
 import { ref, shallowRef } from "vue-demi";
-import { noop, until } from "@vueuse/core";
 import type {
-  UnInstance,
-  UnResponse,
   UnCancelTokenSource,
   UnConfig,
   UnData,
+  UnInstance,
+  UnResponse,
 } from "./index";
-import { un, UnError } from "./index";
+import { UnError, un } from "./index";
 
 /** Align with v10.8.0 */
 
@@ -187,6 +187,7 @@ export function useUn<T = any, R = UnResponse<T>, D = any>(
         .then(() => (error.value ? reject(error.value) : resolve(result)));
     });
   const promise = {
+    // biome-ignore lint/suspicious/noThenProperty: <explanation>
     then: (...args) => waitUntilFinished().then(...args),
     catch: (...args) => waitUntilFinished().catch(...args),
   } as Promise<OverallUseUnReturn<T, R, D>>;
diff --git a/packages/core/src/core/Un.ts b/packages/core/src/core/Un.ts
index 452a6fe..08f9d9c 100644
--- a/packages/core/src/core/Un.ts
+++ b/packages/core/src/core/Un.ts
@@ -1,9 +1,9 @@
-import { buildFullPath, buildUrl, mergeConfig } from "../utils";
 import type { UnConfig, UnData, UnResponse } from "../types";
+import { buildFullPath, buildUrl, mergeConfig } from "../utils";
 import {
   UnInterceptorManager,
-  UnInterceptorManagerHandlerFulfilled,
-  UnInterceptorManagerHandlerRejected,
+  type UnInterceptorManagerHandlerFulfilled,
+  type UnInterceptorManagerHandlerRejected,
 } from "./UnInterceptorManager";
 import { dispatchRequest } from "./dispatchRequest";
 
@@ -141,10 +141,13 @@ export class Un<T = UnData, D = UnData> {
       return await this._request(configOrUrl, config);
     } catch (error) {
       if (error instanceof Error) {
+        // biome-ignore lint/suspicious/noImplicitAnyLet: <explanation>
         let dummy;
         Error.captureStackTrace
-          ? Error.captureStackTrace((dummy = {}))
-          : (dummy = new Error());
+          ? // biome-ignore lint/suspicious/noAssignInExpressions: <explanation>
+            Error.captureStackTrace((dummy = {}))
+          : // biome-ignore lint/suspicious/noAssignInExpressions: <explanation>
+            (dummy = new Error());
         // slice off the Error: ... line
         const stack = dummy.stack ? dummy.stack.replace(/^.+\n/, "") : "";
         if (!error.stack) {
@@ -154,7 +157,7 @@ export class Un<T = UnData, D = UnData> {
           stack &&
           !String(error.stack).endsWith(stack.replace(/^.+\n.+\n/, ""))
         ) {
-          error.stack += "\n" + stack;
+          error.stack += `\n${stack}`;
         }
       }
       throw error;
diff --git a/packages/core/src/core/UnCancelToken.test.ts b/packages/core/src/core/UnCancelToken.test.ts
index d4a4068..797b21c 100644
--- a/packages/core/src/core/UnCancelToken.test.ts
+++ b/packages/core/src/core/UnCancelToken.test.ts
@@ -1,8 +1,9 @@
-import { describe, it, expect } from "vitest";
-import { noop } from "@modyqyw/utils";
-import { UnCancelToken, UnCanceler } from "./UnCancelToken";
+import { describe, expect, it } from "vitest";
+import { UnCancelToken, type UnCanceler } from "./UnCancelToken";
 import { UnCanceledError } from "./UnCanceledError";
 
+function noop() {}
+
 describe("core:UnCancelToken", () => {
   describe("constructor", () => {
     it("throws when executor is not specified", () => {
diff --git a/packages/core/src/core/UnCancelToken.ts b/packages/core/src/core/UnCancelToken.ts
index b2443cc..616253e 100644
--- a/packages/core/src/core/UnCancelToken.ts
+++ b/packages/core/src/core/UnCancelToken.ts
@@ -9,13 +9,15 @@ export interface UnCancelStatic {
   new (message?: string): UnCancel;
 }
 
-export interface UnCanceler<T = UnData, D = UnData> {
-  (message?: string, config?: UnConfig<T, D>, task?: UnTask): void;
-}
+export type UnCanceler<T = UnData, D = UnData> = (
+  message?: string,
+  config?: UnConfig<T, D>,
+  task?: UnTask,
+) => void;
 
-export interface UnCancelTokenListener {
-  (reason: UnCancel | PromiseLike<UnCancel>): void;
-}
+export type UnCancelTokenListener = (
+  reason: UnCancel | PromiseLike<UnCancel>,
+) => void;
 
 export interface UnCancelTokenSource<T = UnData, D = UnData> {
   token: UnCancelToken;
@@ -51,6 +53,7 @@ export class UnCancelToken<T = UnData, D = UnData> {
       this.listeners = [];
     });
 
+    // biome-ignore lint/suspicious/noThenProperty: <explanation>
     this.promise.then = (onfulfilled) => {
       let _resolve: UnCancelTokenListener;
       const promise = new Promise<UnCancel>((resolve) => {
diff --git a/packages/core/src/core/UnCanceledError.test.ts b/packages/core/src/core/UnCanceledError.test.ts
index f2cecb7..44c7bd0 100644
--- a/packages/core/src/core/UnCanceledError.test.ts
+++ b/packages/core/src/core/UnCanceledError.test.ts
@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { UnCanceledError } from "./UnCanceledError";
 
 describe("core:UnCanceledError", () => {
diff --git a/packages/core/src/core/UnError.test.ts b/packages/core/src/core/UnError.test.ts
index d557f05..e2bb1fc 100644
--- a/packages/core/src/core/UnError.test.ts
+++ b/packages/core/src/core/UnError.test.ts
@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { UnError } from "./UnError";
 
 describe("core::UnError", () => {
diff --git a/packages/core/src/core/UnInterceptorManager.ts b/packages/core/src/core/UnInterceptorManager.ts
index c0bbcd5..8e8fa1c 100644
--- a/packages/core/src/core/UnInterceptorManager.ts
+++ b/packages/core/src/core/UnInterceptorManager.ts
@@ -5,13 +5,11 @@ export interface UnInterceptorOptions<T = UnData, D = UnData> {
   runWhen?: (config: UnConfig<T, D>) => boolean;
 }
 
-export interface UnInterceptorManagerHandlerFulfilled<V> {
-  (value: V): V | Promise<V>;
-}
+export type UnInterceptorManagerHandlerFulfilled<V> = (
+  value: V,
+) => V | Promise<V>;
 
-export interface UnInterceptorManagerHandlerRejected {
-  (error: any): any;
-}
+export type UnInterceptorManagerHandlerRejected = (error: any) => any;
 
 export interface UnInterceptorManagerHandler<V, T = V, D = UnData>
   extends UnInterceptorOptions<T, D> {
diff --git a/packages/core/src/core/dispatchRequest.ts b/packages/core/src/core/dispatchRequest.ts
index a35d10c..22fa84a 100644
--- a/packages/core/src/core/dispatchRequest.ts
+++ b/packages/core/src/core/dispatchRequest.ts
@@ -1,7 +1,7 @@
 import { adapters, requestAdapter } from "../adapters";
 import type { UnConfig, UnData } from "../types";
-import { isUnCancel } from "./isUnCancel";
 import { UnCanceledError } from "./UnCanceledError";
+import { isUnCancel } from "./isUnCancel";
 
 const throwIfCancellationRequested = <T = UnData, D = UnData>(
   config: UnConfig<T, D>,
diff --git a/packages/core/src/core/isUnCancel.test.ts b/packages/core/src/core/isUnCancel.test.ts
index 98f4ceb..b87f488 100644
--- a/packages/core/src/core/isUnCancel.test.ts
+++ b/packages/core/src/core/isUnCancel.test.ts
@@ -1,6 +1,6 @@
-import { describe, it, expect } from "vitest";
-import { isUnCancel } from "./isUnCancel";
+import { describe, expect, it } from "vitest";
 import { UnCanceledError } from "./UnCanceledError";
+import { isUnCancel } from "./isUnCancel";
 
 describe("core:isCancel", () => {
   it("returns true if value is a CanceledError", () => {
diff --git a/packages/core/src/core/isUnCancel.ts b/packages/core/src/core/isUnCancel.ts
index ef82183..86b6c22 100644
--- a/packages/core/src/core/isUnCancel.ts
+++ b/packages/core/src/core/isUnCancel.ts
@@ -1,4 +1,4 @@
-import { UnCancel } from "./UnCancelToken";
+import type { UnCancel } from "./UnCancelToken";
 
 export const isUnCancel = (value: any): value is UnCancel =>
   value?.isUnCanceledError === true;
diff --git a/packages/core/src/core/isUnError.test.ts b/packages/core/src/core/isUnError.test.ts
index c2569f2..aa4d204 100644
--- a/packages/core/src/core/isUnError.test.ts
+++ b/packages/core/src/core/isUnError.test.ts
@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { UnError } from "./UnError";
 import { isUnError } from "./isUnError";
 
diff --git a/packages/core/src/core/isUnError.ts b/packages/core/src/core/isUnError.ts
index 5574e14..6756df3 100644
--- a/packages/core/src/core/isUnError.ts
+++ b/packages/core/src/core/isUnError.ts
@@ -1,5 +1,5 @@
 import type { UnData } from "../types";
-import { UnError } from "./UnError";
+import type { UnError } from "./UnError";
 
 export const isUnError = <T = UnData, D = UnData>(
   value: any,
diff --git a/packages/core/src/core/settle.test.ts b/packages/core/src/core/settle.test.ts
index 0f26cf3..0bd7fea 100644
--- a/packages/core/src/core/settle.test.ts
+++ b/packages/core/src/core/settle.test.ts
@@ -1,4 +1,4 @@
-import { describe, it, expect, vi, beforeEach, type Mock } from "vitest";
+import { type Mock, beforeEach, describe, expect, it, vi } from "vitest";
 import type { UnResponse } from "../types";
 import { settle } from "./settle";
 
diff --git a/packages/core/src/index.test.ts b/packages/core/src/index.test.ts
index 4870c66..856c8e7 100644
--- a/packages/core/src/index.test.ts
+++ b/packages/core/src/index.test.ts
@@ -1,18 +1,18 @@
-import { expect, it, describe } from "vitest";
-import { defaults } from "./defaults";
+import { describe, expect, it } from "vitest";
+import { un } from ".";
+import { version } from "../package.json";
 import {
+  HttpStatusCode,
   Un,
-  UnInterceptorManager,
-  UnCanceledError,
   UnCancelToken,
-  isUnCancel,
+  UnCanceledError,
   UnError,
+  UnInterceptorManager,
+  isUnCancel,
   isUnError,
-  HttpStatusCode,
 } from "./core";
+import { defaults } from "./defaults";
 import { mergeConfig } from "./utils";
-import { un } from ".";
-import { version } from "../package.json";
 
 describe("index", () => {
   it("un should be defined", () => {
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index ca182a0..e3ff60b 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -1,18 +1,18 @@
 import { version } from "../package.json";
 import {
   HttpStatusCode,
-  isUnError,
   Un,
-  UnCancel,
-  UnCanceledError,
+  type UnCancel,
   UnCancelToken,
-  UnCancelTokenStatic,
+  type UnCancelTokenStatic,
+  UnCanceledError,
   UnError,
   isUnCancel,
+  isUnError,
 } from "./core";
 import { defaults } from "./defaults";
+import type { UnConfig, UnData, UnResponse } from "./types";
 import { extend, mergeConfig } from "./utils";
-import { UnConfig, UnData, UnResponse } from "./types";
 
 export interface UnInstance<T = UnData, D = UnData> extends Un<T, D> {
   <TT = T, DD = D, R = UnResponse<TT, DD>>(
diff --git a/packages/core/src/types/adapter.ts b/packages/core/src/types/adapter.ts
index 43d6974..1e09b0d 100644
--- a/packages/core/src/types/adapter.ts
+++ b/packages/core/src/types/adapter.ts
@@ -2,6 +2,6 @@ import type { UnData } from "./common";
 import type { UnConfig } from "./config";
 import type { UnPromise } from "./promise";
 
-export interface UnAdapter<T = UnData, D = UnData> {
-  (config: UnConfig<T, D>): UnPromise<T, D>;
-}
+export type UnAdapter<T = UnData, D = UnData> = (
+  config: UnConfig<T, D>,
+) => UnPromise<T, D>;
diff --git a/packages/core/src/types/common.ts b/packages/core/src/types/common.ts
index 160f9ee..7a75700 100644
--- a/packages/core/src/types/common.ts
+++ b/packages/core/src/types/common.ts
@@ -26,13 +26,9 @@ export type UnHeaders = Record<string, any>;
 
 export type UnParams = Record<string, any>;
 
-export interface UnParamsSerializer {
-  (params?: UnParams): string;
-}
+export type UnParamsSerializer = (params?: UnParams) => string;
 
-export interface UnValidateStatus {
-  (status: number): boolean | null;
-}
+export type UnValidateStatus = (status: number) => boolean | null;
 
 export interface UnGenericAbortSignal {
   readonly aborted: boolean;
@@ -51,20 +47,18 @@ export interface UnFile {
   uri?: string;
 }
 
-export interface UnOnProgress {
-  (response?: {
-    /** 当前上传/下载百分比 */
-    progress?: number;
-    /** 已经上传的数据长度，单位 Bytes */
-    totalBytesSent?: number;
-    /** 预期需要上传的数据总长度，单位 Bytes */
-    totalBytesExpectedToSend?: number;
-    /** 已经下载的数据长度，单位 Bytes */
-    totalBytesWritten?: number;
-    /** 预期需要下载的数据总长度，单位 Bytes */
-    totalBytesExpectedToWrite?: number;
-  }): void;
-}
+export type UnOnProgress = (response?: {
+  /** 当前上传/下载百分比 */
+  progress?: number;
+  /** 已经上传的数据长度，单位 Bytes */
+  totalBytesSent?: number;
+  /** 预期需要上传的数据总长度，单位 Bytes */
+  totalBytesExpectedToSend?: number;
+  /** 已经下载的数据长度，单位 Bytes */
+  totalBytesWritten?: number;
+  /** 预期需要下载的数据总长度，单位 Bytes */
+  totalBytesExpectedToWrite?: number;
+}) => void;
 
 export type UnFileType = "image" | "video" | "audio";
 
diff --git a/packages/core/src/types/config.ts b/packages/core/src/types/config.ts
index c454d74..f3370a9 100644
--- a/packages/core/src/types/config.ts
+++ b/packages/core/src/types/config.ts
@@ -1,19 +1,19 @@
-import { UnCancelToken } from "../core/UnCancelToken";
+import type { UnCancelToken } from "../core/UnCancelToken";
+import type { UnAdapter } from "./adapter";
 import type {
   UnData,
-  UnHeaders,
-  UnMethod,
   UnDataType,
-  UnResponseType,
+  UnFile,
+  UnFileType,
   UnGenericAbortSignal,
+  UnHeaders,
+  UnMethod,
   UnOnProgress,
-  UnFileType,
+  UnParams,
   UnParamsSerializer,
+  UnResponseType,
   UnValidateStatus,
-  UnFile,
-  UnParams,
 } from "./common";
-import type { UnAdapter } from "./adapter";
 
 export interface UnConfig<T = UnData, D = UnData> {
   /** 用于请求的服务器 URL */
diff --git a/packages/core/src/utils/buildDownloadConfig.ts b/packages/core/src/utils/buildDownloadConfig.ts
index 306d21a..6ab0fcb 100644
--- a/packages/core/src/utils/buildDownloadConfig.ts
+++ b/packages/core/src/utils/buildDownloadConfig.ts
@@ -1,4 +1,4 @@
-import type { UnData, UnConfig } from "../types";
+import type { UnConfig, UnData } from "../types";
 import { buildFullPath } from "./buildFullPath";
 import { buildUrl } from "./buildUrl";
 
diff --git a/packages/core/src/utils/buildFullPath.test.ts b/packages/core/src/utils/buildFullPath.test.ts
index 1db975b..5ff00a2 100644
--- a/packages/core/src/utils/buildFullPath.test.ts
+++ b/packages/core/src/utils/buildFullPath.test.ts
@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { buildFullPath } from "./buildFullPath";
 
 describe("utils::buildFullPath", () => {
diff --git a/packages/core/src/utils/buildRequestConfig.ts b/packages/core/src/utils/buildRequestConfig.ts
index 7fe823c..609cd87 100644
--- a/packages/core/src/utils/buildRequestConfig.ts
+++ b/packages/core/src/utils/buildRequestConfig.ts
@@ -1,4 +1,4 @@
-import type { UnData, UnConfig } from "../types";
+import type { UnConfig, UnData } from "../types";
 import { buildFullPath } from "./buildFullPath";
 import { buildUrl } from "./buildUrl";
 
diff --git a/packages/core/src/utils/buildUploadConfig.ts b/packages/core/src/utils/buildUploadConfig.ts
index 044415b..da442b2 100644
--- a/packages/core/src/utils/buildUploadConfig.ts
+++ b/packages/core/src/utils/buildUploadConfig.ts
@@ -1,4 +1,4 @@
-import type { UnData, UnConfig } from "../types";
+import type { UnConfig, UnData } from "../types";
 import { buildFullPath } from "./buildFullPath";
 import { buildUrl } from "./buildUrl";
 
diff --git a/packages/core/src/utils/buildUrl.test.ts b/packages/core/src/utils/buildUrl.test.ts
index 2a10454..e5cc634 100644
--- a/packages/core/src/utils/buildUrl.test.ts
+++ b/packages/core/src/utils/buildUrl.test.ts
@@ -1,5 +1,5 @@
 import URLSearchParams from "@ungap/url-search-params";
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { buildUrl } from "./buildUrl";
 
 describe("utils::buildUrl", () => {
diff --git a/packages/core/src/utils/buildUrl.ts b/packages/core/src/utils/buildUrl.ts
index fa064ec..34f6be1 100644
--- a/packages/core/src/utils/buildUrl.ts
+++ b/packages/core/src/utils/buildUrl.ts
@@ -10,9 +10,10 @@ export const buildUrl = (
     return url;
   }
 
+  let newUrl = url;
   const hashIndex = url.indexOf("#");
   if (hashIndex !== -1) {
-    url = url.slice(0, hashIndex);
+    newUrl = newUrl.slice(0, hashIndex);
   }
 
   const serializerParams = paramsSerializer
@@ -22,8 +23,8 @@ export const buildUrl = (
       : qs.stringify(params);
 
   if (serializerParams) {
-    url += (url.includes("?") ? "&" : "?") + serializerParams;
+    newUrl += (newUrl.includes("?") ? "&" : "?") + serializerParams;
   }
 
-  return url;
+  return newUrl;
 };
diff --git a/packages/core/src/utils/combineUrls.test.ts b/packages/core/src/utils/combineUrls.test.ts
index 836eaa3..acebfce 100644
--- a/packages/core/src/utils/combineUrls.test.ts
+++ b/packages/core/src/utils/combineUrls.test.ts
@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { combineUrls } from "./combineUrls";
 
 describe("utils::combineUrls", () => {
diff --git a/packages/core/src/utils/combineUrls.ts b/packages/core/src/utils/combineUrls.ts
index 6f661a7..58abf09 100644
--- a/packages/core/src/utils/combineUrls.ts
+++ b/packages/core/src/utils/combineUrls.ts
@@ -1,5 +1,5 @@
 export const combineUrls = (baseUrl: string, relativeUrl: string) => {
   return relativeUrl
-    ? baseUrl.replace(/\/?\/$/, "") + "/" + relativeUrl.replace(/^\/+/, "")
+    ? `${baseUrl.replace(/\/?\/$/, "")}/${relativeUrl.replace(/^\/+/, "")}`
     : baseUrl;
 };
diff --git a/packages/core/src/utils/extend.test.ts b/packages/core/src/utils/extend.test.ts
index 6c0eb0b..d67f806 100644
--- a/packages/core/src/utils/extend.test.ts
+++ b/packages/core/src/utils/extend.test.ts
@@ -1,8 +1,8 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { extend } from "./extend";
 
-describe("utils::extend", function () {
-  it("should be mutable", function () {
+describe("utils::extend", () => {
+  it("should be mutable", () => {
     const a: Record<string, any> = {};
     const b: Record<string, any> = { foo: 123 };
 
@@ -11,7 +11,7 @@ describe("utils::extend", function () {
     expect(a.foo).toEqual(b.foo);
   });
 
-  it("should extend properties", function () {
+  it("should extend properties", () => {
     let a: Record<string, any> = { foo: 123, bar: 456 };
     const b: Record<string, any> = { bar: 789 };
 
@@ -21,7 +21,7 @@ describe("utils::extend", function () {
     expect(a.bar).toEqual(789);
   });
 
-  it("should bind to thisArg", function () {
+  it("should bind to thisArg", () => {
     const a: Record<string, any> = {};
     const b: Record<string, any> = {
       getFoo: function getFoo() {
diff --git a/packages/core/src/utils/forEach.test.ts b/packages/core/src/utils/forEach.test.ts
index b28b148..9665900 100644
--- a/packages/core/src/utils/forEach.test.ts
+++ b/packages/core/src/utils/forEach.test.ts
@@ -1,18 +1,18 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { forEach } from "./forEach";
 
-describe("utils::forEach", function () {
-  it("should loop over an array", function () {
+describe("utils::forEach", () => {
+  it("should loop over an array", () => {
     let sum = 0;
 
-    forEach([1, 2, 3, 4, 5], function (val) {
+    forEach([1, 2, 3, 4, 5], (val) => {
       sum += val;
     });
 
     expect(sum).toEqual(15);
   });
 
-  it("should loop over object keys", function () {
+  it("should loop over object keys", () => {
     let keys = "";
     let vals = 0;
     const obj = {
@@ -21,7 +21,7 @@ describe("utils::forEach", function () {
       r: 3,
     };
 
-    forEach(obj, function (v, k) {
+    forEach(obj, (v, k) => {
       keys += k;
       vals += v;
     });
@@ -30,22 +30,22 @@ describe("utils::forEach", function () {
     expect(vals).toEqual(6);
   });
 
-  it("should handle undefined gracefully", function () {
+  it("should handle undefined gracefully", () => {
     let count = 0;
 
-    forEach(undefined, function () {
+    forEach(undefined, () => {
       count++;
     });
 
     expect(count).toEqual(0);
   });
 
-  it("should make an array out of non-array argument", function () {
+  it("should make an array out of non-array argument", () => {
     let count = 0;
 
     forEach(
-      function () {},
-      function () {
+      () => {},
+      () => {
         count++;
       },
     );
@@ -53,12 +53,12 @@ describe("utils::forEach", function () {
     expect(count).toEqual(1);
   });
 
-  it("should handle non object prototype gracefully", function () {
+  it("should handle non object prototype gracefully", () => {
     let count = 0;
     const data = Object.create(null);
     data.foo = "bar";
 
-    forEach(data, function () {
+    forEach(data, () => {
       count++;
     });
 
diff --git a/packages/core/src/utils/forEach.ts b/packages/core/src/utils/forEach.ts
index 7699f81..eb5ad5e 100644
--- a/packages/core/src/utils/forEach.ts
+++ b/packages/core/src/utils/forEach.ts
@@ -12,32 +12,30 @@ export function forEach(
 ) {
   if (obj === null || obj === undefined) return;
 
-  let i;
-  let l;
+  let i: number;
+  let l: number;
 
   // Force an array if not already something iterable
-  if (typeof obj !== "object") {
-    obj = [obj];
-  }
+  const object = typeof obj !== "object" ? [obj] : obj;
 
-  if (Array.isArray(obj)) {
+  if (Array.isArray(object)) {
     // Iterate over array values
-    for (i = 0, l = obj.length; i < l; i++) {
-      fn.call(null, obj[i], i, obj);
+    for (i = 0, l = object.length; i < l; i++) {
+      fn.call(null, object[i], i, object);
     }
   } else {
     // Iterate over object keys
     const keys = allOwnKeys
-      ? Object.getOwnPropertyNames(obj).filter(
+      ? Object.getOwnPropertyNames(object).filter(
           (key) => key !== "constructor" && !key.startsWith("_"),
         )
-      : Object.keys(obj);
+      : Object.keys(object);
     const len = keys.length;
-    let key;
+    let key: string;
 
     for (i = 0; i < len; i++) {
       key = keys[i];
-      fn.call(null, obj[key], key, obj);
+      fn.call(null, object[key], key, object);
     }
   }
 }
diff --git a/packages/core/src/utils/isAbsoluteUrl.test.ts b/packages/core/src/utils/isAbsoluteUrl.test.ts
index 8ccac95..eb58d73 100644
--- a/packages/core/src/utils/isAbsoluteUrl.test.ts
+++ b/packages/core/src/utils/isAbsoluteUrl.test.ts
@@ -1,4 +1,4 @@
-import { describe, it, expect } from "vitest";
+import { describe, expect, it } from "vitest";
 import { isAbsoluteUrl } from "./isAbsoluteUrl";
 
 describe("utils::isAbsoluteUrl", () => {