refactor(core/fetch): optimize perfomance, improve types

core/fetch/oxlint.config.ts

@@ -1,4 +1,4 @@
-import { defineConfig } from 'oxlint';
 import { base, compose, imports, stylistic, typescript } from '@robonen/oxlint';
+import { defineConfig } from 'oxlint';
 
 export default defineConfig(compose(base, typescript, imports, stylistic));

core/fetch/package.json

@@ -42,6 +42,9 @@
     "dev": "vitest dev",
     "build": "tsdown"
   },
+  "dependencies": {
+    "@robonen/stdlib": "workspace:*"
+  },
   "devDependencies": {
     "@robonen/oxlint": "workspace:*",
     "@robonen/tsconfig": "workspace:*",

core/fetch/src/error.test.ts

@@ -1,5 +1,5 @@
-import { describe, expect, it } from 'vitest';
 import { FetchError, createFetchError } from './error';
+import { describe, expect, it } from 'vitest';
 import type { FetchContext } from './types';
 
 function makeContext(overrides: Partial<FetchContext> = {}): FetchContext {

core/fetch/src/error.ts

@@ -1,4 +1,5 @@
-import type { FetchContext, FetchOptions, FetchRequest, FetchResponse, IFetchError } from './types';
+import type { FetchContext, FetchErrorOptions, FetchRequest, FetchResponse, IFetchError, ResponseType } from './types';
+import { omit } from '@robonen/stdlib';
 
 /**
  * @name FetchError
@@ -8,18 +9,27 @@ import type { FetchContext, FetchOptions, FetchRequest, FetchResponse, IFetchErr
  * @since 0.0.1
  */
 export class FetchError<T = unknown> extends Error implements IFetchError<T> {
-  request?: FetchRequest;
+  request: FetchRequest | undefined;
-  options?: FetchOptions;
+  options: FetchErrorOptions | undefined;
-  response?: FetchResponse<T>;
+  response: FetchResponse<T> | undefined;
-  data?: T;
+  data: T | undefined;
-  status?: number;
+  status: number | undefined;
-  statusText?: string;
+  statusText: string | undefined;
-  statusCode?: number;
+  statusCode: number | undefined;
-  statusMessage?: string;
+  statusMessage: string | undefined;
 
   constructor(message: string) {
     super(message);
     this.name = 'FetchError';
+
+    this.request = undefined;
+    this.options = undefined;
+    this.response = undefined;
+    this.data = undefined;
+    this.status = undefined;
+    this.statusText = undefined;
+    this.statusCode = undefined;
+    this.statusMessage = undefined;
   }
 }
 
@@ -33,13 +43,13 @@ export class FetchError<T = unknown> extends Error implements IFetchError<T> {
  *
  * @since 0.0.1
  */
-export function createFetchError<T = unknown>(context: FetchContext<T>): FetchError<T> {
+export function createFetchError<T = unknown, R extends ResponseType = ResponseType>(context: FetchContext<T, R>): FetchError<T> {
   const url
     = typeof context.request === 'string'
       ? context.request
       : context.request instanceof URL
         ? context.request.href
-        : (context.request as Request).url;
+        : context.request.url;
 
   const statusPart = context.response
     ? `${context.response.status} ${context.response.statusText}`
@@ -55,7 +65,7 @@ export function createFetchError<T = unknown>(context: FetchContext<T>): FetchEr
   const error = new FetchError<T>(message);
 
   error.request = context.request;
-  error.options = context.options;
+  error.options = omit(context.options, ['onRequest', 'onRequestError', 'onResponse', 'onResponseError', 'retryDelay', 'parseResponse']);
 
   if (context.response !== undefined) {
     error.response = context.response;

core/fetch/src/fetch.test.ts

@@ -1,4 +1,5 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import type { Fetch } from './types';
 import { FetchError } from './error';
 import { createFetch } from './fetch';
 
@@ -10,8 +11,8 @@ function makeFetchMock(
   body: unknown = { ok: true },
   init: ResponseInit = { status: 200 },
   contentType = 'application/json',
-): ReturnType<typeof vi.fn> {
+) {
-  return vi.fn().mockResolvedValue(
+  return vi.fn<Fetch>().mockResolvedValue(
     new Response(typeof body === 'string' ? body : JSON.stringify(body), {
       ...init,
       headers: { 'content-type': contentType, ...init.headers },
@@ -478,14 +479,14 @@ describe('response types', () => {
 
   it('uses a custom parseResponse function', async () => {
     const fetchMock = vi
-      .fn()
+      .fn<Fetch>()
       .mockResolvedValue(
         new Response('{"value":10}', { headers: { 'content-type': 'application/json' } }),
       );
     const $fetch = createFetch({ fetch: fetchMock });
 
-    const data = await $fetch<{ value: number }>('https://api.example.com/custom', {
+    const data = await $fetch<{ value: number; custom: boolean }>('https://api.example.com/custom', {
-      parseResponse: text => ({ ...JSON.parse(text) as object, custom: true }),
+      parseResponse: text => ({ ...(JSON.parse(text) as { value: number }), custom: true }),
     });
 
     expect(data).toEqual({ value: 10, custom: true });

core/fetch/src/fetch.ts

@@ -1,5 +1,5 @@
-import type { ResponseMap, $Fetch, CreateFetchOptions, FetchContext, FetchOptions, FetchRequest, FetchResponse, ResponseType } from './types';
+import type { $Fetch, CreateFetchOptions, FetchContext, FetchOptions, FetchRequest, FetchResponse, MappedResponseType, ResponseType } from './types';
-import { createFetchError } from './error';
+import { FetchError, createFetchError } from './error';
 import {
   NULL_BODY_STATUSES,
   buildURL,
@@ -10,11 +10,11 @@ import {
   joinURL,
   resolveFetchOptions,
 } from './utils';
+import { isFunction, isNumber, isString, retry } from '@robonen/stdlib';
 
-// ---------------------------------------------------------------------------
+function assignResponseData(response: { _data?: unknown }, data: unknown): void {
-// V8: module-level Set — initialised once, never mutated, allows V8 to
+  response._data = data;
-// embed the set reference as a constant in compiled code.
+}
-// ---------------------------------------------------------------------------
 
 /** HTTP status codes that trigger automatic retry by default */
 const DEFAULT_RETRY_STATUS_CODES: ReadonlySet<number> = /* @__PURE__ */ new Set([
@@ -37,15 +37,6 @@ const DEFAULT_RETRY_STATUS_CODES: ReadonlySet<number> = /* @__PURE__ */ new Set(
  * @category Fetch
  * @description Creates a configured $fetch instance
  *
- * V8 optimisation notes:
- * - All inner objects are created with a fixed property set so V8 can reuse
- *   their hidden class across invocations (no dynamic property additions).
- * - `Error.captureStackTrace` is called only when available (V8 / Node.js)
- *   to produce clean stack traces without internal frames.
- * - Retry and timeout paths avoid allocating closures on the hot path.
- * - `NULL_BODY_STATUSES` / `DEFAULT_RETRY_STATUS_CODES` are frozen module-
- *   level Sets, so their `.has()` calls are always monomorphic.
- *
  * @param {CreateFetchOptions} [globalOptions={}] - Global defaults and custom fetch implementation
  * @returns {$Fetch} Configured fetch instance
  *
@@ -55,82 +46,104 @@ export function createFetch(globalOptions: CreateFetchOptions = {}): $Fetch {
   const fetchImpl = globalOptions.fetch ?? globalThis.fetch;
 
   // -------------------------------------------------------------------------
-  // Error handler — shared between network errors and 4xx/5xx responses
+  // executeFetch — performs a single fetch attempt (no retry logic)
   // -------------------------------------------------------------------------
 
-  async function onError(context: FetchContext): Promise<FetchResponse<unknown>> {
+  async function executeFetch<T = unknown, R extends ResponseType = 'json'>(context: FetchContext<T, R>): Promise<FetchResponse<T>> {
-    // Explicit user-triggered abort should not be retried automatically
+    // Actual fetch call
-    const isAbort
+    try {
-      = context.error !== undefined
+      context.response = await fetchImpl(context.request, context.options as RequestInit);
-        && context.error.name === 'AbortError'
+    }
-        && context.options.timeout === undefined;
+    catch (err) {
+      context.error = err as Error;
 
-    if (!isAbort && context.options.retry !== false) {
+      if (context.options.onRequestError !== undefined) {
-      // Default retry count: 0 for payload methods, 1 for idempotent methods
+        await callHooks(
-      const maxRetries
+          context as FetchContext<T, R> & { error: Error },
-        = typeof context.options.retry === 'number'
+          context.options.onRequestError,
-          ? context.options.retry
+        );
-          : isPayloadMethod(context.options.method ?? 'GET')
-            ? 0
-            : 1;
-
-      if (maxRetries > 0) {
-        const responseStatus = context.response?.status ?? 500;
-        const retryStatusCodes = context.options.retryStatusCodes;
-        const shouldRetry
-          = retryStatusCodes !== undefined
-            ? retryStatusCodes.includes(responseStatus)
-            : DEFAULT_RETRY_STATUS_CODES.has(responseStatus);
-
-        if (shouldRetry) {
-          const retryDelay
-            = typeof context.options.retryDelay === 'function'
-              ? context.options.retryDelay(context)
-              : (context.options.retryDelay ?? 0);
-
-          if (retryDelay > 0) {
-            await new Promise<void>((resolve) => {
-              setTimeout(resolve, retryDelay);
-            });
       }
 
-          return $fetchRaw(context.request, {
+      throw createFetchError(context);
-            ...context.options,
+    }
-            retry: maxRetries - 1,
+
-          });
+    // Response body parsing
+    const method = context.options.method ?? 'GET';
+    const hasBody
+      = context.response.body !== null
+        && !NULL_BODY_STATUSES.has(context.response.status)
+        && method !== 'HEAD';
+
+    if (hasBody) {
+      const responseType
+        = context.options.parseResponse !== undefined
+          ? 'json'
+          : (context.options.responseType
+            ?? detectResponseType(context.response.headers.get('content-type') ?? ''));
+
+      switch (responseType) {
+        case 'json': {
+          const text = await context.response.text();
+          if (text) {
+            context.response._data
+              = context.options.parseResponse !== undefined
+                ? context.options.parseResponse(text)
+                : JSON.parse(text);
+          }
+          break;
+        }
+        case 'stream': {
+          assignResponseData(context.response, context.response.body);
+          break;
+        }
+        default: {
+          assignResponseData(context.response, await context.response[responseType]());
         }
       }
     }
 
-    const error = createFetchError(context);
+    if (context.options.onResponse !== undefined) {
-
+      await callHooks(
-    // V8 / Node.js — clip internal frames from the error stack trace
+        context as FetchContext<T, R> & { response: FetchResponse<T> },
-    if (typeof Error.captureStackTrace === 'function') {
+        context.options.onResponse,
-      Error.captureStackTrace(error, $fetchRaw);
+      );
     }
 
-    throw error;
+    if (
+      !context.options.ignoreResponseError
+      && context.response.status >= 400
+      && context.response.status < 600
+    ) {
+      if (context.options.onResponseError !== undefined) {
+        await callHooks(
+          context as FetchContext<T, R> & { response: FetchResponse<T> },
+          context.options.onResponseError,
+        );
+      }
+
+      throw createFetchError(context);
+    }
+
+    return context.response;
   }
 
   // -------------------------------------------------------------------------
   // $fetchRaw — returns the full Response object with a parsed `_data` field
   // -------------------------------------------------------------------------
 
-  const $fetchRaw: $Fetch['raw'] = async function $fetchRaw<
+  const $fetchRaw = async function $fetchRaw<
     T = unknown,
     R extends ResponseType = 'json',
   >(
     _request: FetchRequest,
-    _options: FetchOptions<R, T> = {} as FetchOptions<R, T>,
+    _options?: FetchOptions<R, T>,
-  ): Promise<FetchResponse<T>> {
+  ): Promise<FetchResponse<MappedResponseType<R, T>>> {
-    // V8: object literal with a fixed shape — V8 allocates a single hidden
-    // class for all context objects created by this function.
     const context: FetchContext<T, R> = {
       request: _request,
       options: resolveFetchOptions(
         _request,
         _options,
-        globalOptions.defaults as FetchOptions<R, T>,
+        globalOptions.defaults,
       ),
       response: undefined,
       error: undefined,
@@ -146,7 +159,7 @@ export function createFetch(globalOptions: CreateFetchOptions = {}): $Fetch {
     }
 
     // URL transformations — only when request is a plain string
-    if (typeof context.request === 'string') {
+    if (isString(context.request)) {
       if (context.options.baseURL !== undefined) {
         context.request = joinURL(context.options.baseURL, context.request);
       }
@@ -163,7 +176,7 @@ export function createFetch(globalOptions: CreateFetchOptions = {}): $Fetch {
       if (isJSONSerializable(context.options.body)) {
         const contentType = context.options.headers.get('content-type');
 
-        if (typeof context.options.body !== 'string') {
+        if (!isString(context.options.body)) {
           context.options.body
             = contentType === 'application/x-www-form-urlencoded'
               ? new URLSearchParams(
@@ -198,81 +211,80 @@ export function createFetch(globalOptions: CreateFetchOptions = {}): $Fetch {
           : timeoutSignal;
     }
 
-    // Actual fetch call
+    // -----------------------------------------------------------------------
+    // Retry configuration — computed once, not per attempt
+    // -----------------------------------------------------------------------
+
+    const retryDisabled = context.options.retry === false;
+    const maxRetries = retryDisabled
+      ? 0
+      : isNumber(context.options.retry)
+        ? context.options.retry
+        : isPayloadMethod(method)
+          ? 0
+          : 1;
+
+    if (maxRetries === 0) {
       try {
-      context.response = await fetchImpl(context.request, context.options as RequestInit);
+        return await executeFetch(context) as FetchResponse<MappedResponseType<R, T>>;
       }
       catch (err) {
-      context.error = err as Error;
+        const error = err instanceof FetchError ? err : createFetchError(context);
 
-      if (context.options.onRequestError !== undefined) {
+        if (isFunction(Error.captureStackTrace)) {
-        await callHooks(
+          Error.captureStackTrace(error, $fetchRaw);
-          context as FetchContext<T, R> & { error: Error },
+        }
-          context.options.onRequestError,
+
+        throw error;
+      }
+    }
+
+    // Retry path — delegates to stdlib retry with iterative while-loop
+    try {
+      return await retry(
+        async ({ stop }) => {
+          try {
+            return await executeFetch(context) as FetchResponse<MappedResponseType<R, T>>;
+          }
+          catch (error) {
+            // User-initiated abort (not timeout) should not be retried
+            const isAbort
+              = context.error !== undefined
+                && context.error.name === 'AbortError'
+                && context.options.timeout === undefined;
+
+            if (isAbort) {
+              stop(error);
+            }
+
+            throw error;
+          }
+        },
+        {
+          // stdlib retry counts total attempts; fetch `retry` means retries only
+          times: maxRetries + 1,
+          delay: isFunction(context.options.retryDelay)
+            ? () => (context.options.retryDelay as (ctx: FetchContext<T, R>) => number)(context)
+            : (context.options.retryDelay ?? 0),
+          shouldRetry: () => {
+            const status = context.response?.status ?? 500;
+            return context.options.retryStatusCodes !== undefined
+              ? context.options.retryStatusCodes.includes(status)
+              : DEFAULT_RETRY_STATUS_CODES.has(status);
+          },
+        },
       );
     }
+    catch (err) {
+      const error = err instanceof FetchError ? err : createFetchError(context);
 
-      return (await onError(context)) as FetchResponse<T>;
+      // V8 / Node.js — clip internal frames from the error stack trace
+      if (isFunction(Error.captureStackTrace)) {
+        Error.captureStackTrace(error, $fetchRaw);
       }
 
-    // Response body parsing
+      throw error;
-    const hasBody
-      = context.response.body !== null
-        && !NULL_BODY_STATUSES.has(context.response.status)
-        && method !== 'HEAD';
-
-    if (hasBody) {
-      const responseType
-        = context.options.parseResponse !== undefined
-          ? 'json'
-          : (context.options.responseType
-            ?? detectResponseType(context.response.headers.get('content-type') ?? ''));
-
-      // V8: switch over a string constant — compiled to a jump table
-      switch (responseType) {
-        case 'json': {
-          const text = await context.response.text();
-          if (text) {
-            context.response._data
-              = context.options.parseResponse !== undefined
-                ? context.options.parseResponse(text)
-                : (JSON.parse(text) as T);
     }
-          break;
-        }
-        case 'stream': {
-          context.response._data = context.response.body as unknown as T;
-          break;
-        }
-        default: {
-          context.response._data = (await context.response[responseType]()) as T;
-        }
-      }
-    }
-
-    if (context.options.onResponse !== undefined) {
-      await callHooks(
-        context as FetchContext<T, R> & { response: FetchResponse<T> },
-        context.options.onResponse,
-      );
-    }
-
-    if (
-      !context.options.ignoreResponseError
-      && context.response.status >= 400
-      && context.response.status < 600
-    ) {
-      if (context.options.onResponseError !== undefined) {
-        await callHooks(
-          context as FetchContext<T, R> & { response: FetchResponse<T> },
-          context.options.onResponseError,
-        );
-      }
-
-      return (await onError(context)) as FetchResponse<T>;
-    }
-
-    return context.response;
   };
 
   // -------------------------------------------------------------------------
@@ -282,9 +294,9 @@ export function createFetch(globalOptions: CreateFetchOptions = {}): $Fetch {
   const $fetch = async function $fetch<T = unknown, R extends ResponseType = 'json'>(
     request: FetchRequest,
     options?: FetchOptions<R, T>,
-  ): Promise<InferResponseType<R, T>> {
+  ): Promise<MappedResponseType<R, T>> {
     const response = await $fetchRaw<T, R>(request, options);
-    return response._data as InferResponseType<R, T>;
+    return response._data as MappedResponseType<R, T>;
   } as $Fetch;
 
   $fetch.raw = $fetchRaw;
@@ -317,8 +329,3 @@ export function createFetch(globalOptions: CreateFetchOptions = {}): $Fetch {
 
   return $fetch;
 }
-
-/** Resolves the inferred return value type from a ResponseType key */
-type InferResponseType<R extends ResponseType, T> = R extends keyof ResponseMap
-  ? ResponseMap[R]
-  : T;

core/fetch/src/index.ts

@@ -1,3 +1,5 @@
+import { createFetch } from './fetch';
+
 export { createFetch } from './fetch';
 export { FetchError, createFetchError } from './error';
 export {
@@ -14,6 +16,7 @@ export type {
   CreateFetchOptions,
   Fetch,
   FetchContext,
+  FetchErrorOptions,
   FetchHook,
   FetchHooks,
   FetchOptions,
@@ -21,8 +24,6 @@ export type {
   FetchResponse,
   IFetchError,
   MappedResponseType,
-  MaybeArray,
-  MaybePromise,
   ResponseMap,
   ResponseType,
   ResolvedFetchOptions,

core/fetch/src/types.ts

@@ -1,3 +1,5 @@
+import type { MaybePromise, ReadonlyArrayable } from '@robonen/stdlib';
+
 // --------------------------
 // Fetch API
 // --------------------------
@@ -50,8 +52,8 @@ export interface $Fetch {
   /** Shorthand for HEAD requests */
   head(
     request: FetchRequest,
-    options?: Omit<FetchOptions<'text', never>, 'method'>,
+    options?: Omit<FetchOptions, 'method'>,
-  ): Promise<FetchResponse<never>>;
+  ): Promise<FetchResponse<unknown>>;
 }
 
 // --------------------------
@@ -69,7 +71,7 @@ export interface FetchOptions<R extends ResponseType = 'json', T = unknown>
   /** Base URL prepended to all relative request URLs */
   baseURL?: string;
   /** Request body — plain objects are automatically JSON-serialized */
-  body?: BodyInit | Record<string, unknown> | unknown[] | null;
+  body?: RequestInit['body'] | Record<string, unknown> | unknown[] | null;
   /** Suppress throwing on 4xx/5xx responses */
   ignoreResponseError?: boolean;
   /** URL query parameters serialized and appended to the request URL */
@@ -139,15 +141,12 @@ export interface FetchContext<T = unknown, R extends ResponseType = 'json'> {
   error?: Error;
 }
 
-export type MaybePromise<T> = T | Promise<T>;
-export type MaybeArray<T> = T | readonly T[];
-
 /**
  * @name FetchHook
  * @category Fetch
  * @description A function invoked at a specific point in the fetch lifecycle
  */
-export type FetchHook<C extends FetchContext = FetchContext> = (context: C) => MaybePromise<void>;
+export type FetchHook<C = FetchContext> = (context: C) => MaybePromise<void>;
 
 /**
  * @name FetchHooks
@@ -156,13 +155,13 @@ export type FetchHook<C extends FetchContext = FetchContext> = (context: C) => M
  */
 export interface FetchHooks<T = unknown, R extends ResponseType = 'json'> {
   /** Called before the request is sent */
-  onRequest?: MaybeArray<FetchHook<FetchContext<T, R>>>;
+  onRequest?: ReadonlyArrayable<FetchHook<FetchContext<T, R>>>;
   /** Called when the request itself throws (e.g. network error, timeout) */
-  onRequestError?: MaybeArray<FetchHook<FetchContext<T, R> & { error: Error }>>;
+  onRequestError?: ReadonlyArrayable<FetchHook<FetchContext<T, R> & { error: Error }>>;
   /** Called after a successful response is received and parsed */
-  onResponse?: MaybeArray<FetchHook<FetchContext<T, R> & { response: FetchResponse<T> }>>;
+  onResponse?: ReadonlyArrayable<FetchHook<FetchContext<T, R> & { response: FetchResponse<T> }>>;
   /** Called when the response status is 4xx or 5xx */
-  onResponseError?: MaybeArray<FetchHook<FetchContext<T, R> & { response: FetchResponse<T> }>>;
+  onResponseError?: ReadonlyArrayable<FetchHook<FetchContext<T, R> & { response: FetchResponse<T> }>>;
 }
 
 // --------------------------
@@ -210,6 +209,17 @@ export interface FetchResponse<T> extends Response {
 // Error
 // --------------------------
 
+/**
+ * @name FetchErrorOptions
+ * @category Fetch
+ * @description Subset of FetchOptions stored on FetchError — strips lifecycle hooks,
+ * parseResponse, and retryDelay callback that are invariant in T/R
+ */
+export type FetchErrorOptions = Omit<
+  FetchOptions<ResponseType>,
+  keyof FetchHooks | 'parseResponse' | 'retryDelay'
+>;
+
 /**
  * @name IFetchError
  * @category Fetch
@@ -217,7 +227,7 @@ export interface FetchResponse<T> extends Response {
  */
 export interface IFetchError<T = unknown> extends Error {
   request?: FetchRequest;
-  options?: FetchOptions;
+  options?: FetchErrorOptions;
   response?: FetchResponse<T>;
   data?: T;
   status?: number;
@@ -234,4 +244,4 @@ export interface IFetchError<T = unknown> extends Error {
 export type Fetch = typeof globalThis.fetch;
 
 /** A fetch request — URL string, URL object, or Request object */
-export type FetchRequest = RequestInfo;
+export type FetchRequest = string | URL | Request;

core/fetch/src/utils.test.ts

@@ -1,4 +1,3 @@
-import { describe, expect, it } from 'vitest';
 import {
   buildURL,
   callHooks,
@@ -8,6 +7,7 @@ import {
   joinURL,
   resolveFetchOptions,
 } from './utils';
+import { describe, expect, it } from 'vitest';
 import type { FetchContext } from './types';
 
 // ---------------------------------------------------------------------------

core/fetch/src/utils.ts

@@ -1,16 +1,11 @@
 import type {
-  FetchContext,
   FetchHook,
   FetchOptions,
   FetchRequest,
   ResolvedFetchOptions,
   ResponseType,
 } from './types';
-
+import { isArray, isFunction } from '@robonen/stdlib';
-// ---------------------------------------------------------------------------
-// V8 optimisation: module-level frozen Sets avoid per-call allocations and
-// allow V8 to treat them as compile-time constants in hidden-class analysis.
-// ---------------------------------------------------------------------------
 
 /** HTTP methods whose requests carry a body */
 const PAYLOAD_METHODS: ReadonlySet<string> = /* @__PURE__ */ new Set(['PATCH', 'POST', 'PUT', 'DELETE']);
@@ -26,7 +21,6 @@ const TEXT_CONTENT_TYPES: ReadonlySet<string> = /* @__PURE__ */ new Set([
   'application/html',
 ]);
 
-/** V8: pre-compiled at module load — avoids per-call RegExp construction */
 const JSON_CONTENT_TYPE_RE = /^application\/(?:[\w!#$%&*.^`~-]*\+)?json(;.+)?$/i;
 
 // ---------------------------------------------------------------------------
@@ -38,8 +32,6 @@ const JSON_CONTENT_TYPE_RE = /^application\/(?:[\w!#$%&*.^`~-]*\+)?json(;.+)?$/i
  * @category Fetch
  * @description Returns true for HTTP methods that carry a request body
  *
- * V8: function is monomorphic — always called with an uppercase string.
- *
  * @param {string} method - Uppercase HTTP method string
  * @returns {boolean}
  *
@@ -54,16 +46,14 @@ export function isPayloadMethod(method: string): boolean {
  * @category Fetch
  * @description Returns true when a value can be serialised with JSON.stringify
  *
- * V8: typeof checks are ordered from most-common to least-common to maximise
- * the probability of an early return and keep the IC monomorphic.
- *
  * @param {unknown} value - Any value
  * @returns {boolean}
  *
  * @since 0.0.1
  */
 export function isJSONSerializable(value: unknown): boolean {
-  if (value === undefined) return false;
+  if (value === undefined)
+    return false;
 
   const type = typeof value;
 
@@ -74,7 +64,7 @@ export function isJSONSerializable(value: unknown): boolean {
   if (type !== 'object') return false;
 
   // Arrays are serialisable
-  if (Array.isArray(value)) return true;
+  if (isArray(value)) return true;
 
   // TypedArrays / ArrayBuffers carry a .buffer property — not JSON-serialisable
   if ((value as Record<string, unknown>).buffer !== undefined) return false;
@@ -108,7 +98,6 @@ export function isJSONSerializable(value: unknown): boolean {
 export function detectResponseType(contentType = ''): ResponseType {
   if (!contentType) return 'json';
 
-  // V8: split once and reuse — avoids calling split multiple times
   const type = contentType.split(';')[0] ?? '';
 
   if (JSON_CONTENT_TYPE_RE.test(type)) return 'json';
@@ -185,16 +174,18 @@ export function joinURL(base: string, path: string): string {
  * @category Fetch
  * @description Merges per-request options with global defaults
  *
- * V8: the returned object always has the same property set (fixed shape),
- * which lets V8 reuse its hidden class across all calls.
- *
  * @since 0.0.1
  */
 export function resolveFetchOptions<R extends ResponseType = 'json', T = unknown>(
   request: FetchRequest,
   input: FetchOptions<R, T> | undefined,
-  defaults: FetchOptions<R, T> | undefined,
+  defaults: FetchOptions | undefined,
-): ResolvedFetchOptions<R, T> {
+): ResolvedFetchOptions<R, T>;
+export function resolveFetchOptions(
+  request: FetchRequest,
+  input: FetchOptions | undefined,
+  defaults: FetchOptions | undefined,
+): ResolvedFetchOptions {
   const headers = mergeHeaders(
     input?.headers ?? (request as Request)?.headers,
     defaults?.headers,
@@ -224,15 +215,17 @@ export function resolveFetchOptions<R extends ResponseType = 'json', T = unknown
   };
 }
 
+/** Header sources accepted by the merge function */
+type HeadersInput = Headers | Record<string, string | undefined> | Array<[string, string]>;
+
 /**
- * Merge two HeadersInit sources into a single Headers instance.
+ * Merge two header sources into a single Headers instance.
  * Input headers override default headers.
  *
- * V8: avoids constructing an intermediate Headers when defaults are absent.
  */
 function mergeHeaders(
-  input: HeadersInit | undefined,
+  input: HeadersInput | undefined,
-  defaults: HeadersInit | undefined,
+  defaults: HeadersInput | undefined,
 ): Headers {
   if (defaults === undefined) {
     return new Headers(input);
@@ -242,9 +235,9 @@ function mergeHeaders(
 
   if (input !== undefined) {
     const src = input instanceof Headers ? input : new Headers(input);
-    for (const [key, value] of src) {
+    src.forEach((value, key) => {
       merged.set(key, value);
-    }
+    });
   }
 
   return merged;
@@ -259,24 +252,21 @@ function mergeHeaders(
  * @category Fetch
  * @description Invokes one or more lifecycle hooks with the given context
  *
- * V8: the single-hook path avoids Array creation; the Array path uses a
- * for-loop with a cached length to stay monomorphic inside the loop body.
- *
  * @since 0.0.1
  */
-export async function callHooks<C extends FetchContext = FetchContext>(
+export async function callHooks<C>(
   context: C,
-  hooks: FetchHook<C> | readonly FetchHook<C>[] | undefined,
+  hooks: FetchHook<C> | ReadonlyArray<FetchHook<C>> | undefined,
 ): Promise<void> {
   if (hooks === undefined) return;
 
-  if (Array.isArray(hooks)) {
+  if (isFunction(hooks)) {
+    await hooks(context);
+    return;
+  }
+
   const len = hooks.length;
   for (let i = 0; i < len; i++) {
-      await (hooks as Array<FetchHook<C>>)[i]!(context);
+    await hooks[i]!(context);
-    }
-  }
-  else {
-    await (hooks as FetchHook<C>)(context);
   }
 }

core/stdlib/src/types/ts/array.ts

@@ -2,3 +2,8 @@
  * A type that can be either a single value or an array of values
  */
 export type Arrayable<T> = T | T[];
+
+/**
+ * A type that can be either a single value or a readonly array of values
+ */
+export type ReadonlyArrayable<T> = T | readonly T[];

pnpm-workspace.yaml

@@ -2,16 +2,22 @@ packages:
   - configs/*
   - core/*
   - infra/*
-  - web/*
+  - vue/*
   - docs
 
 catalog:
+  '@stylistic/eslint-plugin': ^5.10.0
   '@vitest/coverage-v8': ^4.0.18
-  '@vue/test-utils': ^2.4.6
-  jsdom: ^29.0.1
-  oxlint: ^1.2.0
-  tsdown: ^0.12.5
-  vitest: ^4.0.18
   '@vitest/ui': ^4.0.18
-  vue: ^3.5.28
+  '@vue/shared': ^3.5.29
+  '@vue/test-utils': ^2.4.6
+  jsdom: ^28.1.0
   nuxt: ^4.3.1
+  oxlint: ^1.51.0
+  tsdown: ^0.21.0
+  vitest: ^4.0.18
+  vue: ^3.5.29
+
+ignoredBuiltDependencies:
+  - '@parcel/watcher'
+  - esbuild