Error map
window is not defined Angular SSR: ReferenceError: window is not defined / document is not defined / localStorage is not defined
Angular · layer 1, On your device
Centre: this error. First ring: errors it is linked with (7). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (7)
Error: Hydration failed because the initial UI does not match what was rendered on the server
The HTML rendered on the server differs from the first client render, so React (Next.js/Remix) can’t attach to it.
Node.js: [UnhandledPromiseRejection] — This error originated either by throwing inside of an async function without a catch block
A promise rejected and nothing handled it; since Node 15 this crashes the process.
ReferenceError: Cannot access 'x' before initialization
A let/const/class was used before its declaration line ran (temporal dead zone) — often a circular import.
Angular: Error: Cannot find control with name: 'email' (reactive forms)
A `formControlName` points at a control that does not exist in the bound `FormGroup`.
Angular SSR: NG0500: During hydration Angular expected <div> but found <span> (NG0501, NG0502)
The HTML rendered on the server does not match what the browser's Angular app tried to render, so hydration failed and the page w…
Angular build: Error: bundle initial exceeded maximum budget. Budget 1.00 MB was not met by 120.00 kB with a total of 1.12 MB
The production build is larger than the size limits (budgets) in angular.json, and the build is configured to fail.
Angular CLI: Schema validation failed with the following errors: Data path "" must NOT have additional properties(xyz)
`angular.json` (or an option you passed to a builder) contains a property the schema does not allow — a typo, an option removed i…
Two steps away (19)
ReferenceError: x is not defined
Code refers to a variable or function name that doesn’t exist in the current scope.
Error: Objects are not valid as a React child
You tried to render a plain object (or a Promise/Date) directly in JSX; React can only render strings, numbers, elements and arra…
Error: Invalid hook call. Hooks can only be called inside of the body of a function component.
A hook ran outside a function component/custom hook, conditionally — or two copies of React are loaded.
Error: connect ECONNREFUSED 127.0.0.1:5432
Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.
TypeError: Failed to fetch / NetworkError when attempting to fetch resource
The browser couldn’t complete the request at the network level — CORS, DNS, offline, blocked mixed content, or the server refused…
Error [ERR_REQUIRE_ESM]: require() of ES Module not supported
CommonJS code used `require()` on a package that is ES-module-only (node-fetch 3, chalk 5, nanoid 4, got 12…).
TypeError: x is not a function
You called something as a function, but its value is not a function (it’s undefined, a string, an object…).
NameError: name 'x' is not defined
Python doesn’t know the name — it was never assigned/imported in this scope, or it’s misspelled.
TypeError: x is not a constructor
new was used with something that isn’t a class/constructor — usually a wrong import.
Angular: NG0100: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked
A template value changed during the same change-detection cycle in which Angular already checked it (dev-mode only error).
Angular: NG8002: Can't bind to 'ngModel' since it isn't a known property of 'input'
The template uses a property binding that no imported directive provides — for ngModel, FormsModule isn’t imported.
Angular: NG8003: No directive found with exportAs 'ngForm' (template reference variable)
A template reference such as `#f="ngForm"` points at a directive Angular cannot find on that element — the module that provides i…
Angular CLI: Could not find the '@angular-devkit/build-angular:browser' builder's node package / Cannot find module '@angular-devkit/build-angular/package.json'
The build tooling package is missing from `node_modules` — dependencies were not installed or the lockfile/install is broken.
ChunkLoadError: Loading chunk 123 failed.
A lazily loaded JavaScript chunk couldn’t be downloaded — usually because a new deployment removed the old hashed files.
Angular: NG0200: Circular dependency in DI detected for X
Two or more services inject each other (directly or through a chain), so Angular cannot create any of them first.
Angular: NG0201: No provider for X found in NodeInjector
A component or directive asked for a service no injector in its tree provides.
Angular: NG0203: inject() must be called from an injection context such as a constructor, a factory function, a field initializer or a function used with runInInjectionContext
`inject()` was called somewhere Angular is not constructing a class — for example inside a method, a callback or after an `await`.
Angular: NG0300: Multiple components match node with tagname app-x: A and B
Two components in scope share the same selector, so Angular cannot decide which one renders for that tag.
Angular: NG0600: Writing to signals is not allowed in a computed or an effect by default
A `computed()` (or, by default, an `effect()`) tried to call `.set()` or `.update()` on a signal — that creates hidden update loo…
Map another error
Popular: 4035004000xC000007BTypeErrorCritical error404NullPointerException