Fix: TypeError: Converting circular structure to JSON
Fix 'Converting circular structure to JSON' with a replacer function, and find the real source: DOM nodes, Mongoose documents, or Express request objects.
Tag: javascript
246 articles
RSSFix: Error: spawn ENOENT (Node.js child_process)
Fix Node.js 'Error: spawn ENOENT' from child_process.spawn(): PATH resolution, the Windows .cmd/.bat problem, and why shell: true is now discouraged (DEP0190).
Fix: TypeError: Cannot destructure property 'x' of 'y' as it is undefined
Fix JavaScript 'Cannot destructure property of undefined' from a missing argument, a failed API response, or optional chaining that doesn't prevent it.
Fix: Cannot set headers after they are sent to the client
Fix Node.js/Express 'Cannot set headers after they are sent to the client', usually a missing return, double next(), or a duplicate response.
Fix: TypeError: fetch failed (Node.js)
Fix Node.js 'TypeError: fetch failed' by reading error.cause to find what really failed: DNS, a refused connection, a timeout, or a bad certificate.
Fix: TypeError: Failed to fetch (JavaScript, Browser)
Fix 'TypeError: Failed to fetch' by telling apart CORS, mixed content, an ad blocker, and being offline using the browser's Network tab, not the JS error alone.
Fix: Error [ERR_REQUIRE_ESM]: require() of ES Module not supported
Fix Node.js 'Error [ERR_REQUIRE_ESM]: require() of ES Module not supported' by checking your Node version, using dynamic import(), or converting to ESM.
Fix: RangeError: Maximum call stack size exceeded (JavaScript)
Fix JavaScript 'RangeError: Maximum call stack size exceeded': find the runaway recursion, add a base case, fix accidental self-reference, and convert deep recursion to iteration.
Fix: listen EADDRINUSE: address already in use (Node.js)
Fix Node.js 'listen EADDRINUSE: address already in use': find and kill the process on the port (macOS, Linux, Windows), or run your server on a different port.
Fix: pnpm Catalog Protocol Not Working — Cannot Find Catalog, Resolution Errors, and Lockfile Issues
Fix pnpm 9.5+ catalog protocol errors — Cannot find catalog default, ERR_PNPM_CATALOG_ENTRY_INVALID_SPEC, stale lockfile state, and tool incompatibility with catalog: references in monorepos.
Fix: Bun Bundler Not Working — Targets, Format, Externals, Macros, and Code Splitting
How to fix bun build errors — target (browser/bun/node) mismatch, format esm/cjs/iife, externals not respected, Bun macros at compile time, splitting and chunks, plugin API, and Bun.build vs CLI.
Fix: Bun Shell Not Working — $ Template Quoting, Pipes, Exit Codes, and Cross-Platform Scripts
How to fix Bun Shell errors — $ template auto-escape vs raw strings, piping with pipe() vs |, throws on non-zero exit, cwd/env scoping, glob expansion differences, and Windows path handling.
Fix: ESLint Flat Config Not Working — eslint.config.js, ignores, Plugins, and Migration
How to fix ESLint flat config errors — eslint.config.js not found, .eslintrc.json ignored after upgrade, ignores replacing .eslintignore, plugin object form, typescript-eslint integration, monorepo configs, and ESLINT_USE_FLAT_CONFIG.
Fix: Node.js fs.watch Not Working — Cross-Platform Quirks, chokidar Migration, Recursive Watch
How to fix Node.js file watching — fs.watch unreliable on Linux, missing events on save, recursive watch on Windows/macOS, chokidar polling fallback, ignoring patterns, debouncing, and EMFILE errors.
Fix: Node.js Stream pipeline() Not Working — Backpressure, Error Propagation, AbortSignal, and Web Streams Interop
How to fix Node.js stream/promises pipeline errors — uncaught stream errors, backpressure ignored, AbortSignal not propagating, async iterators in pipeline, Transform stream object mode, and converting between Node and Web Streams.
Fix: Node.js Test Runner Not Working — node --test, TypeScript, Mocks, Coverage, and Watch Mode
How to fix Node.js built-in test runner errors — node --test not finding files, ESM vs CJS imports, TypeScript with --experimental-strip-types, mock.method isolation, coverage reporting, and watch mode setup.
Fix: Nx Not Working — project.json Targets, Affected Commands, Caching, and Generators
How to fix Nx errors — nx.json plugin config, project.json target inputs/outputs, nx affected base branch, cache misses, generator schema, custom executors, and nx migrate failures.
Fix: Oxlint Not Working — .oxlintrc.json Config, Rule Mapping, TypeScript, and ESLint Coexistence
How to fix Oxlint errors — .oxlintrc.json not loaded, rules not matching ESLint output, TypeScript files not linted, plugin-react/typescript wiring, IDE extension setup, and running alongside ESLint.
Fix: Passkey / WebAuthn Not Working — rpId, Origin, Conditional UI, and Cross-Device Sign-In
How to fix passkey and WebAuthn errors — rpId mismatch, NotAllowedError, Conditional UI autofill not showing, attestation vs assertion, Safari userVerification quirks, and SimpleWebAuthn library integration.
Fix: Sentry Source Maps Not Working — Release Matching, sentry-cli Upload, Vite/Webpack Plugins
How to fix Sentry source maps errors — minified stack traces, release name mismatch between build and runtime, sentry-cli upload-sourcemaps options, Vite/Webpack/Next.js plugin setup, and hiding maps from public.
Fix: Valibot Not Working — v.pipe Syntax, Error Messages, Async Validation, and Zod Migration
How to fix Valibot errors — v.pipe vs chained methods, parse vs safeParse, async pipelines with v.parseAsync, custom error messages with v.message, optional/nullable variants, Zod migration patterns, and form library integration.
Fix: Bun Test Not Working — Module Mocking, DOM Setup, Coverage, and Watch Mode
How to fix Bun test runner issues — mock.module not isolating, happy-dom setup for DOM tests, --coverage missing files, timer mocks, snapshot updates, TypeScript path aliases, and preload files.
Fix: pnpm Workspace Not Working — workspace:* Protocol, Catalog, Filters, and Hoisting Issues
How to fix pnpm workspace errors — workspace:* not resolving, catalog versions out of sync, --filter not matching, peer deps unmet across packages, shamefully-hoist trade-offs, and publishConfig for releases.
Fix: Deno PermissionDenied — Missing --allow-read, --allow-net, and Other Flags
How to fix Deno PermissionDenied (NotCapable in Deno 2) errors — the right permission flags, path-scoped permissions, deno.json permission sets, and the Deno.permissions API.
Fix: Fastify Not Working — 404, Plugin Encapsulation, and Schema Validation Errors
How to fix Fastify issues — route 404 from plugin encapsulation, reply already sent, FST_ERR_VALIDATION, request.body undefined, @fastify/cors, hooks not running, and TypeScript type inference.
Fix: Kafka Consumer Not Receiving Messages, Connection Refused, and Rebalancing Errors
How to fix Apache Kafka issues — consumer not receiving messages, auto.offset.reset, Docker advertised.listeners, max.poll.interval.ms rebalancing, MessageSizeTooLargeException, and KafkaJS errors.
Fix: OpenAI API Not Working — RateLimitError, 401, 429, and Connection Issues
How to fix OpenAI API errors — RateLimitError (429), AuthenticationError (401), APIConnectionError, context length exceeded, model not found, and SDK v0-to-v1 migration mistakes.
Fix: Vinxi Not Working — Dev Server Not Starting, Routes Not Matching, or Build Failing
How to fix Vinxi server framework issues — app configuration, routers, server functions, middleware, static assets, and deployment to different platforms.
Fix: AutoAnimate Not Working — Transitions Not Playing, List Items Not Animating, or React State Changes Ignored
How to fix @formkit/auto-animate issues — parent ref setup, React useAutoAnimate hook, Vue directive, animation customization, disabling for specific elements, and framework integration.
Fix: Blurhash Not Working — Placeholder Not Rendering, Encoding Failing, or Colors Wrong
How to fix Blurhash image placeholder issues — encoding with Sharp, decoding in React, canvas rendering, Next.js image placeholders, CSS blur fallback, and performance optimization.
Fix: Clack Not Working — Prompts Not Displaying, Spinners Stuck, or Cancel Not Handled
How to fix @clack/prompts issues — interactive CLI prompts, spinners, multi-select, confirm dialogs, grouped tasks, cancellation handling, and building CLI tools with beautiful output.
Fix: CodeMirror Not Working — Editor Not Rendering, Extensions Not Loading, or React State Out of Sync
How to fix CodeMirror 6 issues — basic setup, language and theme extensions, React integration, vim mode, collaborative editing, custom keybindings, and read-only mode.
Fix: Docusaurus Not Working — Build Failing, Sidebar Not Showing, or Plugin Errors
How to fix Docusaurus issues — docs and blog configuration, sidebar generation, custom theme components, plugin setup, MDX compatibility, search integration, and deployment.
Fix: Embla Carousel Not Working — Slides Not Scrolling, Autoplay Not Starting, or Thumbnails Not Syncing
How to fix Embla Carousel issues — React setup, slide sizing, autoplay and navigation plugins, loop mode, thumbnail carousels, responsive breakpoints, and vertical scrolling.
Fix: GSAP Not Working — Animations Not Playing, ScrollTrigger Not Firing, or React Cleanup Issues
How to fix GSAP animation issues — timeline and tween basics, ScrollTrigger setup, React useGSAP hook, cleanup and context, SplitText, stagger animations, and Next.js integration.
Fix: i18next Not Working — Translations Missing, Language Not Switching, or Namespace Errors
How to fix i18next issues — react-i18next setup, translation file loading, namespace configuration, language detection, interpolation, pluralization, and Next.js integration.
Fix: ky Not Working — Requests Failing, Hooks Not Firing, or Retry Not Working
How to fix ky HTTP client issues — instance creation, hooks (beforeRequest, afterResponse), retry configuration, timeout handling, JSON parsing, error handling, and migration from fetch or axios.
Fix: Lottie Not Working — Animation Not Playing, File Not Loading, or React Component Blank
How to fix Lottie animation issues — lottie-react and lottie-web setup, JSON animation loading, playback control, interactivity, lazy loading, and performance optimization.
Fix: Mapbox GL JS Not Working — Map Not Rendering, Markers Missing, or Access Token Invalid
How to fix Mapbox GL JS issues — access token setup, React integration with react-map-gl, markers and popups, custom layers, geocoding, directions, and Next.js configuration.
Fix: pdf-lib Not Working — PDF Not Generating, Fonts Not Embedding, or Pages Blank
How to fix pdf-lib issues — creating PDFs from scratch, modifying existing PDFs, embedding fonts and images, form filling, merging documents, and browser and Node.js usage.
Fix: Paraglide Not Working — Messages Not Loading, Compiler Errors, or Framework Integration Issues
How to fix Paraglide.js i18n issues — message compilation, type-safe translations, SvelteKit and Next.js integration, language switching, and message extraction from existing code.
Fix: PostHog Not Working — Events Not Tracking, Feature Flags Stale, or Session Replay Blank
How to fix PostHog analytics issues — JavaScript and Next.js setup, event capture, feature flags, A/B testing, session replay, user identification, and server-side tracking.
Fix: Prism React Renderer Not Working — No Syntax Colors, Wrong Language, or Custom Theme Not Applying
How to fix prism-react-renderer issues — Highlight component setup, language support, custom themes, line highlighting, copy button, and integration with MDX and documentation sites.
Fix: Pusher Not Working — Events Not Received, Channel Auth Failing, or Connection Dropping
How to fix Pusher real-time issues — client and server setup, channel types, presence channels, authentication endpoints, event binding, connection management, and React integration.
Fix: React PDF Not Working — PDF Not Rendering, Worker Error, or Pages Blank
How to fix react-pdf and @react-pdf/renderer issues — PDF viewer setup, worker configuration, page rendering, text selection, annotations, and generating PDFs in React.
Fix: React Three Fiber Not Working — Canvas Blank, Models Not Loading, or Performance Dropping
How to fix React Three Fiber (R3F) issues — Canvas setup, loading 3D models with useGLTF, lighting, camera controls, animations with useFrame, post-processing, and Next.js integration.
Fix: Sentry Not Working — Errors Not Captured, Source Maps Missing, or Performance Traces Empty
How to fix Sentry issues — SDK initialization, source map uploads, error boundaries, performance monitoring, Next.js integration, release tracking, and alert configuration.
Fix: Sharp Not Working — Installation Failing, Image Not Processing, or Build Errors on Deploy
How to fix Sharp image processing issues — native binary installation, resize and convert operations, Next.js image optimization, Docker setup, serverless deployment, and common platform errors.
Fix: Shiki Not Working — No Syntax Highlighting, Wrong Theme, or Build Errors
How to fix Shiki syntax highlighter issues — basic setup, theme configuration, custom languages, transformer plugins, Next.js and Astro integration, and bundle size optimization.
Fix: View Transitions API Not Working — No Animation Between Pages, Cross-Document Transitions Failing, or Fallback Missing
How to fix View Transitions API issues — same-document transitions, cross-document MPA transitions, view-transition-name CSS, Next.js and Astro integration, custom animations, and browser support.
Fix: Auth.js (NextAuth) Not Working — Session Null, OAuth Callback Error, or CSRF Token Mismatch
How to fix Auth.js and NextAuth.js issues — OAuth provider setup, session handling in App Router and Pages Router, JWT vs database sessions, middleware protection, and credential provider configuration.
Fix: Capacitor Not Working — Build Failing, Plugins Not Loading, or Native Features Not Available
How to fix Capacitor issues — project setup with Ionic or standalone, native plugin access, iOS and Android build errors, live reload, deep links, push notifications, and migration from Cordova.
Fix: Cypress Not Working — Tests Timing Out, Elements Not Found, or cy.intercept Not Matching
How to fix Cypress issues — element selection strategies, async command chaining, cy.intercept for network stubbing, component testing, authentication handling, and flaky test debugging.
Fix: Effect (effect-ts) Not Working — Effect Not Running, Services Missing, or Type Errors
How to fix Effect issues — running effects with Effect.runPromise, Layer and service dependency injection, error channel types, Fiber concurrency, Schema validation, and common TypeScript errors.
Fix: Electron Not Working — Window Not Showing, IPC Not Communicating, or Build Failing
How to fix Electron issues — main and renderer process setup, IPC communication with contextBridge, preload scripts, auto-update, native module rebuilding, and packaging with electron-builder.
Fix: jose JWT Not Working — Token Verification Failing, Invalid Signature, or Key Import Errors
How to fix jose JWT issues — signing and verifying tokens with HS256 and RS256, JWK and JWKS key handling, token expiration, claims validation, and edge runtime compatibility.
Fix: Million.js Not Working — Compiler Errors, Components Not Optimized, or React Compatibility Issues
How to fix Million.js issues — compiler setup with Vite and Next.js, block() optimization rules, component compatibility constraints, automatic mode, and debugging performance gains.
Fix: Nitro Not Working — Server Routes Not Found, Middleware Not Running, or Deploy Failing
How to fix Nitro server engine issues — route handlers, middleware, storage with unstorage, caching, WebSocket support, deployment presets for Cloudflare Workers, Vercel, and Node.js.
Fix: Panda CSS Not Working — Styles Not Applying, Tokens Not Resolving, or Build Errors
How to fix Panda CSS issues — PostCSS setup, panda.config.ts token system, recipe and pattern definitions, conditional styles, responsive design, and integration with Next.js and Vite.
Fix: Qwik Not Working — Components Not Rendering, useSignal Not Reactive, or Serialization Errors
How to fix Qwik issues — component$ boundaries, useSignal and useStore reactivity, serialization with dollar signs, useTask$ and useVisibleTask$, Qwik City routing, and integration with React components.
Fix: Radix UI Not Working — Popover Not Opening, Dialog Closing Immediately, or Styling Breaking
How to fix Radix UI issues — Popover and Dialog setup, controlled vs uncontrolled state, portal rendering, animation with CSS or Framer Motion, accessibility traps, and Tailwind CSS integration.
Fix: Rspack Not Working — Build Failing, Loaders Not Applying, or Dev Server Not Starting
How to fix Rspack issues — configuration migration from webpack, loader compatibility, CSS extraction, module federation, React Fast Refresh, and build performance tuning.
Fix: Svelte 5 Runes Not Working — $state Not Reactive, $derived Not Updating, or $effect Running Twice
How to fix Svelte 5 Runes issues — $state and $state.raw reactivity, $derived computations, $effect lifecycle, $props and $bindable, migration from Svelte 4 stores, and component patterns.
Fix: UnoCSS Not Working — Classes Not Generating, Presets Missing, or Attributify Mode Broken
How to fix UnoCSS issues — Vite plugin setup, preset configuration, attributify mode, icons preset, shortcuts, custom rules, and integration with Next.js, Nuxt, and Astro.
Fix: Wrangler Not Working — Deploy Failing, Bindings Not Found, or D1 Queries Returning Empty
How to fix Wrangler and Cloudflare Workers issues — wrangler.toml configuration, KV and D1 bindings, R2 storage, environment variables, local dev with Miniflare, and deployment troubleshooting.
Fix: Biome Not Working — Rules Not Applied, ESLint Config Not Migrated, or VSCode Extension Ignored
How to fix Biome linter/formatter issues — biome.json configuration, migrating from ESLint and Prettier, VSCode extension setup, CI integration, and rule override syntax.
Fix: Convex Not Working — Query Not Updating, Mutation Throwing Validation Error, or Action Timing Out
How to fix Convex backend issues — query/mutation/action patterns, schema validation, real-time reactivity, file storage, auth integration, and common TypeScript type errors.
Fix: date-fns Not Working — Wrong Timezone Output, Invalid Date, or Locale Not Applied
How to fix date-fns issues — timezone handling with date-fns-tz, parseISO vs new Date, locale import and configuration, DST edge cases, v3 ESM migration, and common format pattern mistakes.
Fix: dnd-kit Not Working — Drag Not Starting, Sort Order Not Updating, or Items Jumping on Drop
How to fix dnd-kit issues — DndContext setup, sensors configuration, useSortable with SortableContext, drag overlays, collision detection algorithms, and accessible drag and drop.
Fix: esbuild Not Working — Plugin Errors, CSS Not Processed, or Output Missing After Build
How to fix esbuild issues — entry points, plugin API, JSX configuration, CSS modules, watch mode, metafile analysis, external packages, and common migration problems from webpack.
Fix: Expo Not Working — Build Failing, Native Module Not Found, or EAS Build Error
How to fix Expo issues — Expo Go vs development builds, native module installation with expo-modules-core, EAS Build configuration, bare workflow setup, and common SDK upgrade problems.
Fix: Framer Motion Not Working — Animation Not Playing, Exit Animation Skipped, or Layout Shift on Mount
How to fix Framer Motion issues — variants, AnimatePresence for exit animations, layout animations, useMotionValue, server component errors, and performance optimization.
Fix: Git Hooks Not Running — Husky Not Working, pre-commit Skipped, or lint-staged Failing
How to fix Git hooks not executing — Husky v9 setup, hook file permissions, lint-staged configuration, pre-commit Python tool, lefthook, and bypassing hooks in CI.
Fix: Hono Not Working — Route Not Matching, Middleware Skipped, or RPC Client Type Mismatch
How to fix Hono framework issues — routing order, middleware chaining, Hono RPC type inference, Cloudflare Workers bindings, validator integration, and runtime compatibility.
Fix: HTMX Not Working — hx-get Request Not Firing, Swap Not Updating DOM, or Response Ignored
How to fix HTMX issues — attribute syntax, target and swap strategies, out-of-band swaps, event handling, CSP configuration, response headers, and debugging HTMX requests.
Fix: Jotai Not Working — Atom Not Updating, Derived Atom Out of Sync, or atomWithStorage Hydration Error
How to fix Jotai state management issues — atom scope, derived atoms, async atoms with Suspense, atomWithStorage SSR, useAtomValue vs useSetAtom, and debugging stale state.
Fix: Lucia Auth Not Working — Session Not Created, Middleware Rejecting Valid Sessions, or OAuth Callback Failing
How to fix Lucia auth issues — adapter setup, session validation in middleware, cookie configuration, OAuth provider integration, Next.js App Router setup, and Lucia v3 migration.
Fix: MDX Not Working — Components Not Rendering, Imports Failing, or Frontmatter Not Parsed
How to fix MDX issues — Next.js App Router setup with @next/mdx and next-mdx-remote, custom component mapping, frontmatter parsing with gray-matter, remark and rehype plugins, and TypeScript configuration.
Fix: MSW (Mock Service Worker) Not Working — Handlers Not Intercepting, Browser Not Mocking, or v2 Migration Errors
How to fix Mock Service Worker issues — browser vs Node setup, handler registration, worker start timing, passthrough requests, and common MSW v2 API changes from v1.
Fix: next-intl Not Working — Translations Missing, Locale Not Detected, or Middleware Redirect Loop
How to fix next-intl issues — App Router setup with middleware, useTranslations in server and client components, locale detection, pluralization, number and date formatting, and routing configuration.
Fix: Nuxt Not Working — useFetch Returns Undefined, Server Route 404, or Hydration Mismatch
How to fix Nuxt 3 issues — useFetch vs $fetch, server routes in server/api, composable SSR rules, useAsyncData, hydration errors, and Nitro configuration problems.
Fix: Playwright Not Working — Test Timeout, Selector Not Found, or CI Headless Fails
How to fix Playwright test issues — locator strategies, auto-waiting, network mocking, flaky tests in CI, trace viewer debugging, and common headless browser setup problems.
Fix: React Native Reanimated Not Working — Worklet Error, useAnimatedStyle Not Updating, or Gesture Not Responding
How to fix React Native Reanimated issues — worklet rules, shared values, useAnimatedStyle, Gesture Handler setup, web support, Babel plugin configuration, and Reanimated 3 migration.
Fix: Recharts Not Working — Chart Not Rendering, Tooltip Missing, or ResponsiveContainer Showing Zero Height
How to fix Recharts issues — ResponsiveContainer setup, data format for each chart type, custom tooltips, axis configuration, legends, animations, and TypeScript types.
Fix: Remix Not Working — Loader Returns Undefined, Action Not Triggered, or Nested Route Data Missing
How to fix Remix issues — loader and action setup, nested route outlet, useLoaderData typing, error boundaries, defer with Await, and common React Router v7 migration problems.
Fix: RxJS Not Working — Observable Not Emitting, Memory Leak from Unsubscribed Stream, or Operator Behaving Unexpectedly
How to fix RxJS issues — subscription management, switchMap vs mergeMap vs concatMap, error handling with catchError, Subject types, cold vs hot observables, and Angular async pipe.
Fix: shadcn/ui Not Working — Components Not Rendering, Styles Missing, or Dark Mode Broken
How to fix shadcn/ui issues — Tailwind CSS v4 vs v3 configuration, CSS variables, dark mode setup, component installation, cn() utility, and common errors after adding components.
Fix: SolidJS Not Working — Signal Not Updating, Effect Running Twice, or createResource Data Undefined
How to fix SolidJS reactivity issues — signal access inside JSX, effect dependencies, createResource with loading states, Show and For components, store mutations, and common mistakes coming from React.
Fix: Storybook Not Working — Addon Conflicts, Component Not Rendering, or Build Fails After Upgrade
How to fix Storybook issues — CSF3 story format, addon configuration, webpack vs Vite builder, decorator setup, args not updating component, and Storybook 8 migration problems.
Fix: styled-components Not Working — Styles Not Applying, SSR Flash of Unstyled Content, or Theme Not Available
How to fix styled-components issues — ThemeProvider setup, Next.js SSR with ServerStyleSheet, shouldForwardProp, attrs, TypeScript theme typing, and styled-components v6 migration.
Fix: Supabase Not Working — RLS Policy Blocking Queries, Realtime Not Receiving Updates, or Auth Session Lost
How to fix Supabase issues — Row Level Security policies, realtime subscriptions, storage permissions, auth session with Next.js, edge functions, and common client configuration mistakes.
Fix: SvelteKit Not Working — load Function Errors, Form Actions Failing, or SSR Data Not Available
How to fix SvelteKit issues — load function data flow, +page.server.ts vs +page.ts, form actions with use:enhance, hooks.server.ts, SSR vs CSR mode, and common routing mistakes.
Fix: TanStack Query Not Working — Data Not Fetching, Cache Not Updating, or Mutation Not Triggering Re-render
How to fix TanStack Query (React Query v5) issues — query keys, stale time, enabled flag, mutation callbacks, optimistic updates, QueryClient setup, and SSR with prefetchQuery.
Fix: TanStack Table Not Working — Sorting Not Triggering, Filters Ignored, or Pagination Showing Wrong Data
How to fix TanStack Table (React Table v8) issues — column definitions, server-side sorting and filtering, row selection, virtual rows with TanStack Virtual, and v7 to v8 migration errors.
Fix: Tauri Not Working — Command Not Found, IPC Error, File System Permission Denied, or Build Fails
How to fix Tauri app issues — Rust command registration, invoke IPC, tauri.conf.json permissions, fs scope, window management, and common build errors on Windows/macOS/Linux.
Fix: Tiptap Not Working — Editor Not Rendering, Extensions Missing, or Content Not Saving
How to fix Tiptap editor issues — useEditor setup in React, StarterKit configuration, custom nodes and marks, SSR with Next.js, collaborative editing, and content serialization.
Fix: Turborepo Not Working — Cache Never Hits, Pipeline Not Running, or Workspace Task Fails
How to fix Turborepo issues — turbo.json pipeline configuration, cache keys, remote caching setup, workspace filtering, and common monorepo task ordering mistakes.
Fix: Valtio Not Working — Component Not Re-rendering, Snapshot Stale, or Proxy Mutation Not Tracked
How to fix Valtio state management issues — proxy vs snapshot, useSnapshot for React, subscribe for side effects, derived state with computed, async actions, and Valtio with React Server Components.
Fix: WebAssembly (WASM) Not Working — Module Fails to Load, Memory Error, or JS Interop Broken
How to fix WebAssembly issues — instantiateStreaming vs instantiate, CORS for WASM files, linear memory limits, wasm-bindgen JS interop, imports/exports mismatch, and WASM in bundlers.
Fix: XState Not Working — Machine Not Transitioning, Guards Not Running, or Actor Not Sending Events
How to fix XState v5 issues — state machine definition, guards and actions typed correctly, useMachine hook, createActor, context updates, child actors, and common v4 to v5 migration errors.
Fix: Zustand Not Working — Component Not Re-rendering, State Reset on Refresh, or Selector Causing Infinite Loop
How to fix Zustand state management issues — selector optimization, persist middleware, shallow comparison, devtools setup, slice pattern for large stores, and common subscription mistakes.
Fix: Bun Not Working — Node.js Module Incompatible, Native Addon Fails, or bun test Errors
How to fix Bun runtime issues — Node.js API compatibility, native addons (node-gyp), Bun.serve vs Node http, bun test differences from Jest, and common package incompatibilities.
Fix: ESLint Config Not Working — Rules Ignored, Flat Config Errors, or Plugin Not Found
How to fix ESLint configuration issues — flat config vs legacy config, extends conflicts, parser options, plugin resolution, per-directory overrides, and migrating to ESLint 9.
Fix: Express Middleware Not Working — Order Wrong, Errors Not Caught, or async Errors Silently Dropped
How to fix Express middleware issues — middleware execution order, error-handling middleware signature, async error propagation with next(err), and common middleware misconfigurations.
Fix: IndexedDB Not Working — Transaction Inactive, Upgrade Blocked, or Store Not Found
How to fix IndexedDB issues — transaction lifecycle, version upgrades, blocked events, cursor iteration, IDBKeyRange queries, and using idb wrapper library to avoid callback hell.
Fix: Jest Setup File Not Working — setupFilesAfterFramework Not Running or Globals Not Applied
How to fix Jest setup file issues — setupFilesAfterFramework vs setupFiles, global mocks not applying, @testing-library/jest-dom matchers, module mocking in setup, and TypeScript setup files.
Fix: Pinia Store Not Working — State Not Reactive, Actions Not Updating, or Store Not Found
How to fix Pinia store issues — state reactivity with storeToRefs, getters not updating, actions async patterns, store outside components, SSR hydration, and testing Pinia stores.
Fix: React useTransition Not Working — UI Still Freezes, isPending Never True, or Transition Not Deferred
How to fix React useTransition and startTransition issues — what counts as a transition, Suspense integration, concurrent rendering requirements, and common mistakes that prevent transitions from deferring.
Fix: TypeScript Conditional Types Not Working — infer Not Extracting, Distributive Behavior Unexpected, or Type Resolves to never
How to fix TypeScript conditional type issues — infer keyword usage, distributive conditional types, deferred evaluation, naked type parameters, and common conditional type patterns.
Fix: TypeScript Discriminated Union Error — Property Does Not Exist or Narrowing Not Working
How to fix TypeScript discriminated union errors — type guards, exhaustive checks, narrowing with in operator, never type, and common patterns for tagged unions.
Fix: TypeScript Template Literal Type Error — Type Not Assignable or Inference Fails
How to fix TypeScript template literal type errors — string combination types, conditional inference, Extract and mapped types with template literals, and common pitfalls.
Fix: Vue Slot Not Working — Named Slots Not Rendering or Scoped Slot Data Not Accessible
How to fix Vue 3 slot issues — v-slot syntax, named slots, scoped slots passing data, default slot content, fallback content, and dynamic slot names.
Fix: Vue Router Params Not Updating — Component Not Re-rendering or beforeRouteUpdate Not Firing
How to fix Vue Router params not updating when navigating between same-route paths — watch $route, beforeRouteUpdate, onBeforeRouteUpdate, and component reuse behavior explained.
Fix: Web Worker Not Working — postMessage Ignored, Cannot Import Module, or Worker Crashes Silently
How to fix Web Worker issues — postMessage data cloning, module workers, error handling, SharedArrayBuffer setup, Comlink, and common reasons workers silently fail.
Fix: Zod Validation Not Working — safeParse Returns Wrong Error, transform Breaks Type, or discriminatedUnion Fails
How to fix Zod schema validation issues — parse vs safeParse, transform and preprocess, refine for cross-field validation, discriminatedUnion, error formatting, and common schema mistakes.
Fix: Node.js Stream Error — Pipe Not Working, Backpressure, or Premature Close
How to fix Node.js stream issues — pipe and pipeline errors, backpressure handling, Transform streams, async iteration, error propagation, and common stream anti-patterns.
Fix: React Testing Library Not Finding Element — Unable to Find Role or Text
How to fix React Testing Library query failures — getByRole vs getByText, async queries, accessible names, waitFor patterns, custom queries, and common selector mistakes.
Fix: Vite Proxy Not Working — API Requests Not Forwarded or 404/502 Errors
How to fix Vite dev server proxy issues — proxy configuration in vite.config.ts, path rewriting, WebSocket proxying, HTTPS targets, and common misconfigurations.
Fix: Vue Teleport Not Rendering — Content Not Appearing at Target Element
How to fix Vue Teleport not working — target element not found, SSR with Teleport, disabled prop, multiple Teleports to the same target, and timing issues.
Fix: Jest Async Test Timeout — Exceeded 5000ms or Test Never Resolves
How to fix Jest async test timeouts — missing await, unresolved Promises, done callback misuse, global timeout configuration, fake timers, and async setup/teardown issues.
Fix: Jest Coverage Not Collected — Files Missing from Coverage Report
How to fix Jest coverage not collecting all files — collectCoverageFrom config, coverage thresholds, Istanbul ignore comments, ts-jest setup, and Babel transform issues.
Fix: React Portal Event Bubbling Not Working — Events Not Reaching Parent
How to fix React Portal event bubbling — understanding Portal event propagation, modal close on outside click, stopPropagation side effects, focus management, and accessibility.
Fix: React StrictMode Double Render — Side Effects Running Twice in Development
How to fix React StrictMode double render issues — understanding intentional double invocation, fixing side effects, useEffect cleanup, external subscriptions, and production behavior.
Fix: React Suspense Not Working — Boundary Not Catching or Fallback Not Showing
How to fix React Suspense boundaries not triggering — lazy() import syntax, use() hook, data fetching libraries, ErrorBoundary vs Suspense, and Next.js loading.tsx.
Fix: Svelte Store Subscription Leak — Memory Leak from Unsubscribed Stores
How to fix Svelte store subscription memory leaks — auto-subscription with $, manual unsubscribe, derived store cleanup, custom store lifecycle, and SvelteKit SSR store handling.
Fix: TypeScript Function Overload Error — No Overload Matches This Call
How to fix TypeScript function overload errors — overload signature compatibility, implementation signature, conditional types as alternatives, method overloads in classes, and common pitfalls.
Fix: TypeScript Mapped Type Errors — Type is Not Assignable to Mapped Type
How to fix TypeScript mapped type errors — Partial, Required, Readonly, Record, Pick, Omit, conditional types, template literal types, and distributive behavior.
Fix: Vue Composable Not Reactive — ref and reactive Losing Reactivity After Destructuring
How to fix Vue composable reactivity loss — toRefs for destructuring, returning refs vs raw values, reactive object pitfalls, stale closures, and composable design patterns.
Fix: Vue Composition API Reactivity Lost — Destructured Props or Reactive Object Not Updating
How to fix Vue Composition API reactivity loss — destructuring reactive objects, toRefs, storeToRefs, ref vs reactive, watch vs watchEffect, and template not updating.
Fix: Pinia State Not Reactive — Store Changes Not Updating the Component
How to fix Pinia store state not updating components — storeToRefs for destructuring, $patch for partial updates, avoiding reactive() wrapping, getters vs computed, and SSR hydration.
Fix: Webpack Dev Server Not Reloading — HMR and Live Reload Not Working
How to fix Webpack dev server not reloading — Hot Module Replacement configuration, watchFiles settings, polling for Docker/WSL, HMR API for custom modules, and port conflicts.
Fix: Webpack Bundle Size Too Large — Reduce JavaScript Bundle for Faster Load Times
How to reduce Webpack bundle size — code splitting, tree shaking, dynamic imports, bundle analysis, moment.js replacement, lodash optimization, and production build configuration.
Fix: Angular Form Validation Not Working — Validators Not Triggering
How to fix Angular form validation not working — Reactive Forms vs Template-Driven, custom validators, async validators, touched/dirty state, and error message display.
Fix: Angular Lazy Loading Not Working — Routes Not Code-Split
How to fix Angular lazy loading not working — loadChildren syntax, standalone components, route configuration mistakes, preloading strategies, and debugging bundle splits.
Fix: Angular RxJS Memory Leak — Subscriptions Not Unsubscribed
How to fix RxJS memory leaks in Angular — unsubscribing from Observables, takeUntilDestroyed, async pipe, subscription management patterns, and detecting leaks with Chrome DevTools.
Fix: Jest Fake Timers Not Working — setTimeout and setInterval Not Advancing
How to fix Jest fake timers not working — useFakeTimers setup, runAllTimers vs advanceTimersByTime, async timers, React testing with act(), and common timer test mistakes.
Fix: Jest Module Mock Not Working — jest.mock() Has No Effect
How to fix Jest module mocks not working — hoisting behavior, ES module mocks, factory functions, mockReturnValue vs implementation, and clearing mocks between tests.
Fix: Node.js UnhandledPromiseRejection and uncaughtException — Crashing Server
How to handle Node.js uncaughtException and unhandledRejection events — graceful shutdown, error logging, async error boundaries, and keeping servers alive safely.
Fix: React Hydration Error — Text Content Does Not Match
How to fix React hydration errors — server/client HTML mismatches, useEffect for client-only code, suppressHydrationWarning, dynamic content, and Next.js specific hydration issues.
Fix: TanStack Query (React Query) Returning Stale Data — Cache Not Updating
How to fix TanStack Query returning stale cached data — staleTime, invalidateQueries, query key structure, optimistic updates, and cache synchronization after mutations.
Fix: Socket.IO CORS Error — Cross-Origin Connection Blocked
How to fix Socket.IO CORS errors — server-side CORS configuration, credential handling, polling vs WebSocket transport, proxy setup, and common connection failures.
Fix: TypeScript Could Not Find Declaration File, Module Has No Type Information
How to fix TypeScript 'could not find a declaration file for module' errors, installing @types packages, writing custom .d.ts files, module augmentation, and tsconfig paths.
Fix: Vue Computed Property Not Updating — Reactivity Not Triggered
How to fix Vue computed properties not updating — reactive dependency tracking, accessing nested objects, computed setters, watchEffect vs computed, and Vue 3 reactivity pitfalls.
Fix: Vue v-model Not Working on Custom Components — Prop Not Syncing
How to fix Vue v-model on custom components — defineModel, modelValue/update:modelValue pattern, multiple v-model bindings, v-model modifiers, and Vue 2 vs Vue 3 differences.
Fix: Webpack/Vite Path Alias Not Working — Module Not Found with @/ Prefix
How to fix path alias errors in webpack and Vite — configuring resolve.alias, tsconfig paths, babel-plugin-module-resolver, Vite alias configuration, and Jest moduleNameMapper.
Fix: Angular Change Detection Not Working — View Not Updating
How to fix Angular change detection issues — OnPush strategy not triggering, async pipe, markForCheck vs detectChanges, zone.js and zoneless patterns, and manual change detection triggers.
Fix: CSS Container Query Not Working — @container and container-type Issues
How to fix CSS container queries not working — setting container-type correctly, understanding containment scope, fixing @container syntax, and handling browser support and specificity issues.
Fix: Express Async Error Not Being Caught — Unhandled Promise Rejection
How to fix Express async route handlers not passing errors to the error middleware — wrapping async routes, using express-async-errors, global error handlers, and Node.js unhandledRejection events.
Fix: Jest Cannot Transform ES Modules — SyntaxError: Cannot use import statement
How to fix Jest failing with 'Cannot use import statement outside a module' — configuring Babel transforms, using experimental VM modules, migrating to Vitest, and handling ESM-only packages.
Fix: Next.js App Router Fetch Not Caching or Always Stale
How to fix Next.js App Router fetch caching issues — understanding cache behavior, revalidation with next.revalidate, opting out with no-store, cache tags, and debugging stale data.
Fix: Node.js JavaScript Heap Out of Memory
How to fix Node.js 'JavaScript heap out of memory' — increasing heap size, finding memory leaks with heap snapshots, fixing common leak patterns, and stream-based processing for large data.
Fix: React Native Android Build Failed
How to fix React Native Android build failures — SDK version mismatches, Gradle errors, duplicate module issues, Metro bundler problems, and NDK configuration for common build errors.
Fix: Redux State Not Updating — Component Not Re-rendering
How to fix Redux state not updating in components — mutating state directly, stale selectors, missing immer patterns in Redux Toolkit, useSelector mistakes, and debugging with Redux DevTools.
Fix: Svelte Store Not Updating — Reactive Store Issues
How to fix Svelte store not updating the UI — writable vs readable stores, derived stores, subscribe pattern, store mutation vs assignment, and custom store patterns.
Fix: Vue Router Navigation Guard Not Working — beforeEach and Route Guards
How to fix Vue Router navigation guards not working — beforeEach, beforeEnter, in-component guards, async guards, redirect loops, and route meta authentication patterns.
Fix: Webpack Bundle Too Large — Chunk Size Warning
How to reduce Webpack bundle size — code splitting, lazy loading, tree shaking, analyzing the bundle with webpack-bundle-analyzer, replacing heavy dependencies, and configuring splitChunks.
Fix: Axios Network Error — Request Failed with Status Code 0
How to fix Axios 'Network Error' with no status code — CORS blocks, SSL certificate issues, request timeout, no internet connection, and debugging with interceptors.
Fix: ESLint no-unused-vars False Positives and Configuration
How to fix ESLint no-unused-vars false positives — TypeScript types, destructuring ignores, React imports, function arguments, and configuring the rule to match your codebase patterns.
Fix: Express req.body Is undefined
How to fix req.body being undefined in Express — missing body-parser middleware, wrong Content-Type header, middleware order issues, and multipart form data handling.
Fix: Flask CORS Not Working
How to fix CORS errors in Flask — installing flask-cors correctly, handling preflight OPTIONS requests, configuring origins with credentials, route-specific CORS, and debugging missing headers.
Fix: Jest Snapshot Outdated, 1 snapshot obsolete
How to fix Jest snapshot failures, updating outdated snapshots, removing obsolete ones, fixing inline snapshots, preventing brittle snapshot tests, and managing snapshots in CI.
Fix: Next.js CORS Error on API Routes
How to fix CORS errors in Next.js API routes — adding Access-Control headers, handling preflight OPTIONS requests, configuring next.config.js headers, and avoiding common proxy mistakes.
Fix: React useEffect Runs Twice in Development
Why React useEffect runs twice in development with Strict Mode, how to handle the double invocation correctly, when to add cleanup functions, and when the double-run actually reveals a real bug.
Fix: TypeScript Decorators Not Working (experimentalDecorators)
How to fix TypeScript decorators not applying — experimentalDecorators not enabled, emitDecoratorMetadata missing, reflect-metadata not imported, and decorator ordering issues.
Fix: TypeScript Enum Not Working — const enum, isolatedModules, and Runtime Issues
How to fix TypeScript enum problems — const enum with isolatedModules, enums not available at runtime, string vs numeric enums, and migrating to union types or as const objects.
Fix: Vite Environment Variables Not Working
How to fix Vite environment variables showing as undefined — missing VITE_ prefix, wrong .env file for the mode, import.meta.env vs process.env, TypeScript types, and SSR differences.
Fix: CSS Custom Properties (Variables) Not Working or Not Updating
How to fix CSS custom properties not applying — wrong scope, missing fallback values, JavaScript not setting variables on the right element, and how CSS variables interact with media queries and Shadow DOM.
Fix: Node.js Crashing with UnhandledPromiseRejection (--unhandled-rejections)
How to fix Node.js UnhandledPromiseRejectionWarning and process crashes — why unhandled promise rejections crash Node.js 15+, how to add global handlers, find the source of the rejection, and fix async error handling.
Fix: GraphQL 400 Bad Request Error (Query Syntax and Variable Errors)
How to fix GraphQL 400 Bad Request errors — malformed query syntax, variable type mismatches, missing required fields, schema validation failures, and how to debug GraphQL errors from Apollo and fetch.
Fix: Next.js Middleware Not Running (middleware.ts Not Intercepting Requests)
How to fix Next.js middleware not executing — wrong file location, matcher config errors, middleware not intercepting API routes, and how to debug middleware execution in Next.js 13 and 14.
Fix: React Query (TanStack Query) Infinite Refetching Loop
How to fix React Query refetching infinitely — why useQuery keeps fetching, how object and array dependencies cause loops, how to stabilize queryKey, and configure refetch behavior correctly.
Fix: Socket.IO Not Connecting (CORS, Transport, and Namespace Errors)
How to fix Socket.IO connection failures — CORS errors, transport fallback issues, wrong namespace, server not emitting to the right room, and how to debug Socket.IO connections in production.
Fix: TypeScript isolatedModules Errors (const enum, type-only imports)
How to fix TypeScript isolatedModules errors — why const enum fails with Babel and Vite, how to replace const enum, fix re-exported types, and configure isolatedModules correctly for your build tool.
Fix: Vitest Setup Not Working (setupFiles, Mocks, and Global Config Issues)
How to fix Vitest configuration not taking effect — why setupFiles don't run, globals are undefined, mocks don't work, and how to configure Vitest correctly for React, Vue, and Node.js projects.
Fix: ESLint import/no-unresolved Error (Module Exists but ESLint Can't Find It)
How to fix ESLint's import/no-unresolved errors when modules actually resolve correctly — configure eslint-import-resolver-typescript, fix path alias settings, and handle node_modules that ESLint cannot find.
Fix: jest.mock() Not Working — Module Not Being Replaced in Tests
How to fix jest.mock() not intercepting module calls — why mocks are ignored, how to correctly mock ES modules, default exports, named exports, and fix hoisting issues in Jest tests.
Fix: Next.js Build Failed (next build Errors and How to Fix Them)
How to fix Next.js build failures — TypeScript errors blocking production builds, module resolution failures, missing environment variables, static generation errors, and common next build crash causes.
Fix: Vite Build Chunk Size Warning (Some Chunks Are Larger Than 500 kB)
How to fix Vite's chunk size warning — why bundles exceed 500 kB, how to split code with dynamic imports and manualChunks, configure the chunk size limit, and optimize your Vite production build.
Fix: JavaScript NaN === NaN Returns false (NaN Comparison Bugs)
How to fix JavaScript NaN comparison bugs — why NaN !== NaN, the difference between isNaN() and Number.isNaN(), and how to correctly check for NaN in conditionals and array operations.
Fix: React Native Metro Bundler Failed to Start or Bundle
How to fix React Native Metro bundler errors — unable to resolve module, EMFILE too many open files, port already in use, transform cache errors, and Metro failing to start on iOS or Android.
Fix: Stripe Webhook Signature Verification Failed
How to fix Stripe webhook signature verification errors — why Stripe-Signature header validation fails, how to correctly pass the raw request body, and how to debug webhook delivery in the Stripe dashboard.
Fix: Vue 3 Reactive Data Not Updating (ref/reactive Not Triggering Re-render)
How to fix Vue 3 reactive data not updating the UI — why ref and reactive lose reactivity, how to correctly mutate reactive state, and common pitfalls with destructuring and nested objects.
Fix: JavaScript Closure in Loop — All Callbacks Get the Same Value
How to fix the JavaScript closure loop bug where all event handlers or setTimeout callbacks return the same value — using let, IIFE, bind, or forEach instead of var in loops.
Fix: React.memo Not Preventing Re-renders
How to fix React.memo not working — components still re-rendering despite being wrapped in memo, caused by new object/function references, missing useCallback, and incorrect comparison functions.
Fix: TypeScript Generic Type Constraint Errors
How to fix TypeScript generic constraint errors — Type 'X' does not satisfy the constraint 'Y', generic inference failures, constrained generics with extends, and conditional types.
Fix: CORS Not Working in Express (Access-Control-Allow-Origin Missing)
How to fix CORS errors in Express.js — cors middleware not applying, preflight OPTIONS requests failing, credentials not allowed, and specific origin whitelisting issues.
Fix: Next.js Environment Variables Returning undefined
How to fix Next.js environment variables returning undefined — NEXT_PUBLIC prefix rules, server vs client context, .env file loading order, and runtime vs build-time variable access.
Fix: React.lazy and Suspense Errors (Element Type Invalid, Loading Chunk Failed)
How to fix React.lazy and Suspense errors — Element type is invalid, A React component suspended while rendering, Loading chunk failed, and lazy import mistakes with named vs default exports.
Fix: Webpack HMR (Hot Module Replacement) Not Working
How to fix Webpack Hot Module Replacement not updating the browser — HMR connection lost, full page reloads instead of hot updates, and HMR breaking in Docker or behind a proxy.
Fix: UnhandledPromiseRejectionWarning / UnhandledPromiseRejection
How to fix UnhandledPromiseRejectionWarning in Node.js and unhandled promise rejection errors in JavaScript caused by missing catch handlers, async/await mistakes, and event emitter errors.
Fix: Jest Timeout — Exceeded timeout of 5000ms for a test
How to fix Jest 'Exceeded timeout of 5000ms for a test' errors caused by unresolved promises, missing done callbacks, async/await mistakes, and slow database or network calls in tests.
Fix: React Context Not Updating / Re-rendering Components
How to fix React Context not triggering re-renders — caused by mutating state directly, wrong provider placement, stale closures, and missing value changes that React can detect.
Fix: No Routes Matched Location in React Router v6
How to fix 'No routes matched location' in React Router v6 — caused by missing Routes wrapper, wrong path syntax, nested route mismatches, and v5 to v6 migration issues.
Fix: Electron 'require' Is Not Defined Error
Fix the Electron 'require is not defined' error caused by contextIsolation, nodeIntegration changes, and learn to use preload scripts and contextBridge.
Fix: Firebase Permission Denied Error
How to fix the Firebase 'permission denied' or 'Missing or insufficient permissions' error in Firestore and Realtime Database. Covers security rules, authentication state, custom claims, Admin SDK, rule simulators, time-based rules, and document-level permissions.
Fix: Jest Cannot Find Module Error
How to fix the Jest 'Cannot find module' error by configuring moduleNameMapper, moduleDirectories, tsconfig paths, and resolving ESM, monorepo, and dependency issues.
Fix: React Warning: Failed prop type
How to fix the React 'Warning: Failed prop type' error. Covers wrong prop types, missing required props, children type issues, shape and oneOf PropTypes, migrating to TypeScript, default props, and third-party component mismatches.
Fix: SyntaxError: Cannot use import statement outside a module
How to fix 'SyntaxError: Cannot use import statement outside a module' in Node.js, TypeScript, Jest, and browsers by configuring ESM, package.json type, and transpiler settings.
Fix: Express Cannot GET /route (404 Not Found)
How to fix Express.js Cannot GET route 404 error caused by wrong route paths, missing middleware, route order issues, static files, and router mounting problems.
Fix: FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
How to fix the JavaScript heap out of memory error by increasing Node.js memory limits, fixing memory leaks, and optimizing builds in webpack, Vite, and Docker.
Fix: TypeError: x is not a function
How to fix JavaScript TypeError is not a function caused by wrong variable types, missing imports, overwritten variables, incorrect method names, and callback issues.
Fix: Next.js API route 404 Not Found or not responding
How to fix Next.js API route 404 not found errors caused by wrong file paths, App Router vs Pages Router confusion, incorrect exports, and deployment issues.
Fix: Next.js Module not found: Can't resolve 'fs' (or 'path', 'crypto', 'net')
How to fix Next.js Module not found Can't resolve fs error caused by importing Node.js modules in client components, wrong server/client boundaries, and missing polyfills.
Fix: Node.js ERR_MODULE_NOT_FOUND - Cannot find module
How to fix Node.js ERR_MODULE_NOT_FOUND when using ES modules, covering missing file extensions, directory imports, package.json exports, TypeScript paths, and ESM resolution differences.
Fix: npm ERR! enoent ENOENT: no such file or directory
How to fix the npm ENOENT no such file or directory error caused by missing package.json, wrong directory, corrupted node_modules, broken symlinks, and npm cache issues.
Fix: npm ERR! code E404 – Not Found (package not found in registry)
How to fix npm ERR code E404 not found error caused by typos, private registries, scoped packages, deleted packages, and authentication issues.
Fix: npm ERR! Could not resolve peer dependency conflict
How to fix the npm ERR! Could not resolve peer dependency conflict error. Covers --legacy-peer-deps, --force, npm overrides, peerDependenciesMeta, React version conflicts, and debugging with npm ls.
Fix: npm WARN deprecated inflight, glob, rimraf, and Other Package Warnings
npm WARN deprecated [email protected], [email protected], [email protected], @humanwhocodes: which warnings are safe to ignore, which need fixing, and exact steps to silence each one.
Fix: React TypeError: Cannot read property 'map' of undefined
How to fix React TypeError Cannot read property map of undefined caused by uninitialized state, async data loading, wrong API response structure, and missing default values.
Fix: React Cannot update a component while rendering a different component
How to fix React Cannot update a component while rendering a different component caused by setState during render, context updates in render, and Redux dispatch in render.
Fix: React Warning: Each child in a list should have a unique "key" prop
How to fix the React unique key prop warning caused by missing keys in lists, duplicate keys, index keys, nested maps, and dynamic list rendering issues.
Fix: Invalid hook call. Hooks can only be called inside of the body of a function component
How to fix the React Invalid hook call error caused by mismatched React versions, duplicate React copies, calling hooks outside components, and class component usage.
Fix: Objects are not valid as a React child (found: [object Object])
How to fix the React error 'Objects are not valid as a React child' caused by rendering plain objects, Date objects, Promises, or API responses directly in JSX.
Fix: React Hook useEffect has a missing dependency warning
How to fix the React Hook useEffect has a missing dependency warning — covers the exhaustive-deps rule, useCallback, useMemo, refs, proper fetch patterns, and when to safely suppress the lint warning.
Fix: React useState not updating (state not changing after setState)
How to fix React useState not updating. Covers async state updates, functional updates, object mutations, stale closures, setTimeout issues, React 18 batching, props initialization, and debugging state changes.
Fix: TypeScript Argument of type 'X' is not assignable to parameter of type 'Y' (TS2345)
How to fix TypeScript error TS2345 Argument of type is not assignable to parameter of type, covering null narrowing, union types, generics, callback types, type widening, enums, and React event handlers.
Fix: TypeScript error TS2304: Cannot find name 'x'
How to fix TypeScript Cannot find name error caused by missing type declarations, missing imports, wrong tsconfig settings, global types, and DOM API usage.
Fix: TypeScript Could not find a declaration file for module (TS7016)
How to fix the TypeScript TS7016 error 'Could not find a declaration file for module' by installing @types packages, creating declaration files, and configuring tsconfig.json.
Fix: TypeScript Property does not exist on type (TS2339)
How to fix TypeScript error TS2339 'Property does not exist on type'. Covers missing interface properties, type narrowing, optional chaining, intersection types, index signatures, type assertions, type guards, window augmentation, and discriminated unions.
Fix: TypeScript Type 'X | undefined' is not assignable to type 'X'
How to fix TypeScript strict null checks error Type X undefined is not assignable caused by optional values, nullable types, missing guards, and strictNullChecks.
Fix: Vite server connection lost / HMR not working
How to fix the '[vite] server connection lost. Polling for restart...' error and HMR not working. Covers file watcher limits, WebSocket config, Docker polling, WSL2, proxy forwarding, SSL issues, firewall blocking, and dependency pre-bundling.
Fix: Error: error:0308010C:digital envelope routines::unsupported
How to fix the Node.js digital envelope routines unsupported error caused by OpenSSL 3.0 changes in Node.js 17+, with solutions for webpack, Vite, React, and Angular.
Fix: Yarn error Integrity check failed / EINTEGRITY sha512
How to fix Yarn integrity check failed and EINTEGRITY sha512 errors caused by corrupted cache, lock file mismatches, registry issues, and network problems.
Fix: Yarn Integrity Check Failed – Expected and Got Different Results
How to fix the Yarn error 'integrity check failed' or 'Lockfile does not satisfy expected package' caused by corrupted cache, outdated lockfile, or version mismatches.
Fix: CORS Error with Credentials – Access-Control-Allow-Credentials and Wildcard Origin
How to fix CORS errors when using cookies or Authorization headers, including 'Access-Control-Allow-Credentials' and wildcard origin conflicts.
Fix: Next.js Image Optimization Errors – Invalid src, Missing Loader, or Unoptimized
How to fix Next.js Image component errors including 'Invalid src prop', 'hostname not configured', missing loader, and optimization failures in production.
Fix: Webpack Module Not Found – Can't Resolve '<module>' in '<directory>'
How to fix the Webpack error 'Module not found: Error: Can't resolve' caused by missing packages, wrong paths, aliases, or extension resolution issues.
Fix: React Can't Perform a State Update on an Unmounted Component
How to fix the React warning 'Can't perform a React state update on an unmounted component' caused by async operations, subscriptions, or timers.
Fix: VSCode ESLint Extension Not Working – No Errors Shown or Not Running
How to fix VSCode's ESLint extension when it stops highlighting errors, shows no output, or fails to start. Covers flat config, settings, and common misconfigurations.
Fix: React useEffect runs infinitely (infinite loop / maximum update depth exceeded)
How to fix useEffect infinite loops in React — covers missing dependency arrays, referential equality, useCallback, unconditional setState, data fetching cleanup, event listeners, useRef, previous value comparison, and the exhaustive-deps lint rule.
Fix: ESLint Parsing error: Unexpected token (JSX, TypeScript, ES modules)
How to fix ESLint 'Parsing error: Unexpected token' for JSX, TypeScript, and ES module syntax by configuring the correct parser, parserOptions, and ESLint config format.
Fix: CORS preflight request blocked — Response to preflight does not have HTTP ok status
How to fix 'Response to preflight request doesn't pass access control check' and 'preflight channel did not succeed' CORS errors by handling OPTIONS requests, setting correct headers, and configuring your server.
Fix: Module parse failed: Unexpected token (Webpack / Vite / esbuild)
How to fix 'Module parse failed: Unexpected token' in Webpack, Vite, and esbuild by configuring the correct loaders and transforms for JSX, TypeScript, CSS, JSON, and other file types.
Fix: Hydration failed because the initial UI does not match what was rendered on the server (Next.js)
How to fix the Next.js hydration mismatch error. Covers invalid HTML nesting, browser extensions, Date/time differences, useEffect for client-only code, dynamic imports, suppressHydrationWarning, localStorage, third-party scripts, Math.random, auth state, and React portals.
Fix: TS2322 Type 'X' is not assignable to type 'Y'
How to fix TypeScript error TS2322 'Type is not assignable to type'. Covers literal types vs general types, string vs String, union types, interface compatibility, generic constraints, readonly arrays, excess property checking, discriminated unions, type assertions, type widening and narrowing, React event handlers, Promise return types, and enum mismatches.
Fix: SyntaxError: Unexpected token < in JSON at position 0
How to fix 'Unexpected token in JSON at position 0', 'JSON.parse: unexpected character', and 'Unexpected end of JSON input' in JavaScript and TypeScript. Covers API returning HTML instead of JSON, Content-Type mismatches, fetch URL typos, invalid JSON syntax, BOM characters, CORS proxies, and debugging with response.text().
Fix: Loading chunk failed / ChunkLoadError
How to fix 'Loading chunk failed', 'ChunkLoadError', and 'Failed to fetch dynamically imported module' in webpack, Next.js, React, and Vite. Covers stale deployments, CDN caching, publicPath misconfiguration, service worker cache, code splitting, dynamic import retry strategies, React.lazy error boundaries, and Next.js-specific solutions.
Fix: TS2532 Object is possibly 'undefined' / Object is possibly 'null'
How to fix TypeScript errors TS2532 'Object is possibly undefined', TS18048 'Object is possibly undefined', and 'Object is possibly null'. Covers optional chaining, nullish coalescing, type narrowing, non-null assertion, type guards, strictNullChecks, Array.find, Map.get, React useRef, and more.
Fix: Too many re-renders. React limits the number of renders to prevent an infinite loop.
How to fix 'Too many re-renders' in React. Covers calling functions in JSX instead of passing references, setState in the render body, useEffect infinite loops, object/array dependency issues, and how to debug re-renders with React DevTools.
Fix: Module not found: Can't resolve / Cannot find module or its corresponding type declarations
How to fix 'Module not found: Can't resolve' in webpack, Vite, and React, and 'Cannot find module or its corresponding type declarations' in TypeScript. Covers missing packages, wrong import paths, case sensitivity, path aliases, node_modules corruption, monorepo hoisting, barrel files, and asset imports.
Fix: [vite] Internal server error: Failed to resolve import
How to fix Vite's 'Failed to resolve import' error, including 'Does the file exist?', 'Optimized dependency needs to be force included', 'Pre-transform error', and '504 (Outdated Optimize Dep)'. Covers missing packages, path aliases, optimizeDeps, cache clearing, and CJS/monorepo edge cases.
Fix: React Hook "useXxx" is called conditionally. React Hooks must be called in the exact same order in every component render.
How to fix 'React Hook is called conditionally', 'Rendered more hooks than during the previous render', 'Invalid hook call', and other React Hooks order errors. Covers conditional hooks, hooks in loops, hooks after early returns, duplicate React versions, and ESLint setup.
Fix: process.env.VARIABLE_NAME Is Undefined (Node.js, React, Next.js, Vite)
How to fix 'process.env.VARIABLE_NAME is undefined' and environment variables not loading from .env files in Node.js, React, Next.js, Vite, and Docker.
Fix: TypeError: Cannot read properties of undefined (reading 'xxx')
How to fix 'TypeError: Cannot read properties of undefined', 'Cannot read property of undefined', and 'Cannot read properties of null' in JavaScript, TypeScript, and React. Covers optional chaining, async data fetching, destructuring, and nested object access.
Fix: Error Cannot find module in Node.js (MODULE_NOT_FOUND)
How to fix 'Error: Cannot find module' and 'MODULE_NOT_FOUND' in Node.js. Covers missing packages, wrong import paths, node_modules issues, TypeScript moduleResolution, ESM vs CJS, and monorepo hoisting.
Fix: Access to fetch has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header
How to fix 'Access to fetch at ... from origin ... has been blocked by CORS policy: No Access-Control-Allow-Origin header is present on the requested resource' in JavaScript. Covers Express, Django, Flask, Spring Boot, ASP.NET, nginx, Apache, dev proxies, preflight requests, credentials, and edge cases.