Error map

Schema validation failed with the following errors Angular CLI: Schema validation failed with the following errors: Data path "" must NOT have additional properties(xyz)

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Schema validation failed with the following errors — Angular CLI: Schema validation failed with the following errors: Data path "" must NOT have additional properties(xyz) (Angular)Schema vali…NG0200 — Angular: NG0200: Circular dependency in DI detected for X (Angular)NG0200NG0201 — Angular: NG0201: No provider for X found in NodeInjector (Angular)NG0201NG0203 — 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 (Angular)NG0203NG0300 — Angular: NG0300: Multiple components match node with tagname app-x: A and B (Angular)NG0300NG0500 — Angular SSR: NG0500: During hydration Angular expected <div> but found <span> (NG0501, NG0502) (Angular)NG0500NG0600 — Angular: NG0600: Writing to signals is not allowed in a computed or an effect by default (Angular)NG0600NG0912 — Angular: NG0912: Component ID generation collision detected. Components 'A' and 'B' with selector 'app-x' use the same ID (Angular)NG0912NG0955 — Angular: NG0955: The provided track expression resulted in duplicated keys for a given collection (@for) (Angular)NG0955NG02100 — Angular: NG02100: InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe' (Angular)NG02100NG02100 — Angular: NG02100: InvalidPipeArgument: 'Unable to convert "x" into a date' for pipe 'DatePipe' (Angular)NG02100NG04002 — Angular: NG04002: Cannot match any routes. URL Segment: 'x' (Angular)NG04002NG04014 — Angular: NG04014: Invalid configuration of route 'x': one of the following must be provided: component, loadComponent, redirectTo, children or loadChildren (Angular)NG04014NullInjectorError — Angular: NullInjectorError: No provider for X! (Angular)NullInjectorErrorNullInjectorError: No provider for HttpClient! — Angular: NullInjectorError: No provider for HttpClient! — provideHttpClient() missing (Angular)NullInjectorError: …NullInjectorError: No provider for ActivatedRoute! — Angular: NullInjectorError: No provider for ActivatedRoute! (also Router) — usually a unit test (Angular)NullInjectorError: …exceeded maximum budget — 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 (Angular)exceeded maximum bu…NG0950 — Angular: NG0950: Input is required but no value is available yet (input.required / viewChild.required) (Angular)NG0950NG8001 — Angular: NG8001: 'app-item' is not a known element — verify that it is included in the component's imports (Angular)NG8001Cannot find control with name — Angular: Error: Cannot find control with name: 'email' (reactive forms) (Angular)Cannot find control…Could not find the builder's node package — Angular CLI: Could not find the '@angular-devkit/build-angular:browser' builder's node package / Cannot find module '@angular-devkit/build-angular/package.json' (Angular)Could not find the …Hydration failed — Error: Hydration failed because the initial UI does not match what was rendered on the server (React)Hydration failedNG0100 — Angular: NG0100: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked (Angular)NG0100window is not defined — Angular SSR: ReferenceError: window is not defined / document is not defined / localStorage is not defined (Angular)window is not defin…Can't find stylesheet to import — Angular (Sass): Error: Can't find stylesheet to import. @import 'variables'; (Angular)Can't find styleshe…NG6008 — Angular: NG6008: Component X is standalone, and cannot be declared in an NgModule. Did you mean to import it instead? (Angular)NG6008NG8103 — Angular: NG8103: The *ngIf directive was used, but neither the NgIf directive nor the CommonModule was imported (Angular)NG8103NG02200 — Angular: NG02200: Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays (Angular)NG02200NG8004 — Angular: NG8004: No pipe found with name 'async' / 'date' / 'translate' — pipe not imported (Angular)NG8004You provided 'undefined' where a stream was expected — RxJS: TypeError: You provided 'undefined' where a stream was expected. You can provide an Observable, Promise, ReadableStream, Array, AsyncIterable, or Iterable. (Angular)You provided 'undef…EmptyError — RxJS: EmptyError: no elements in sequence (firstValueFrom / lastValueFrom on an empty Observable) (Angular)EmptyErrorTS2322 — TS2322: Type 'X' is not assignable to type 'Y' (TypeScript)TS2322404 — HTTP 404 Not Found (HTTP)404Cannot GET /route on refresh — Angular (production): Cannot GET /dashboard — 404 when refreshing or opening a deep link (Angular)Cannot GET /route o…

Directly related (12)

NG0200Angular

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.

NG0201Angular

Angular: NG0201: No provider for X found in NodeInjector

A component or directive asked for a service no injector in its tree provides.

NG0203Angular

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`.

NG0300Angular

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.

NG0500Angular

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…

NG0600Angular

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…

NG0912Angular

Angular: NG0912: Component ID generation collision detected. Components 'A' and 'B' with selector 'app-x' use the same ID

Angular generated the same internal id for two different components — usually two components with the same selector, template and…

NG0955Angular

Angular: NG0955: The provided track expression resulted in duplicated keys for a given collection (@for)

In an `@for` block (or `trackBy`), two items produced the same tracking key, so Angular cannot match them to DOM nodes reliably.

NG02100Angular

Angular: NG02100: InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe'

The `async` pipe received a plain object or array instead of an Observable or Promise.

NG02100Angular

Angular: NG02100: InvalidPipeArgument: 'Unable to convert "x" into a date' for pipe 'DatePipe'

The `date` pipe was given a value it cannot turn into a Date — an invalid string, a non-ISO format, `null` handled wrongly or a s…

NG04002Angular

Angular: NG04002: Cannot match any routes. URL Segment: 'x'

The router found no route for the URL you navigated to — missing route, wrong path, or an unloaded lazy route.

NG04014Angular

Angular: NG04014: Invalid configuration of route 'x': one of the following must be provided: component, loadComponent, redirectTo, children or loadChildren

A route object has a path but nothing for the router to render or load.

Two steps away (21)

NullInjectorErrorAngular

Angular: NullInjectorError: No provider for X!

Angular’s dependency injection couldn’t find a provider for a service/token the component needs.

NullInjectorError: No provider for HttpClient!Angular

Angular: NullInjectorError: No provider for HttpClient! — provideHttpClient() missing

A service or component injects `HttpClient`, but HTTP support was never added to the app's providers.

NullInjectorError: No provider for ActivatedRoute!Angular

Angular: NullInjectorError: No provider for ActivatedRoute! (also Router) — usually a unit test

A component injects `ActivatedRoute` or `Router`, but no router providers exist in the injector — typical in unit tests or when t…

exceeded maximum budgetAngular

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.

NG0950Angular

Angular: NG0950: Input is required but no value is available yet (input.required / viewChild.required)

A required signal input or query was read before Angular set it — in the constructor or too early in the lifecycle.

NG8001Angular

Angular: NG8001: 'app-item' is not a known element — verify that it is included in the component's imports

The template uses a tag Angular does not recognise as a component — it was never imported (standalone) or declared/exported (NgMo…

Cannot find control with nameAngular

Angular: Error: Cannot find control with name: 'email' (reactive forms)

A `formControlName` points at a control that does not exist in the bound `FormGroup`.

Could not find the builder's node packageAngular

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.

Hydration failedReact

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.

NG0100Angular

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).

window is not definedAngular

Angular SSR: ReferenceError: window is not defined / document is not defined / localStorage is not defined

Code that only works in a browser ran during server-side rendering, where `window`, `document` and `localStorage` do not exist.

Can't find stylesheet to importAngular

Angular (Sass): Error: Can't find stylesheet to import. @import 'variables';

A Sass `@import` / `@use` cannot resolve its path — wrong relative path, missing underscore partial, or the include path is not c…

NG6008Angular

Angular: NG6008: Component X is standalone, and cannot be declared in an NgModule. Did you mean to import it instead?

A standalone component, directive or pipe was listed in an NgModule's `declarations` array.

NG8103Angular

Angular: NG8103: The *ngIf directive was used, but neither the NgIf directive nor the CommonModule was imported

A standalone component uses `*ngIf`, `*ngFor` or `ngClass` without importing the directive — or should migrate to the built-in `@…

NG02200Angular

Angular: NG02200: Cannot find a differ supporting object '[object Object]' of type 'object'. NgFor only supports binding to Iterables such as Arrays

`*ngFor` (or `@for`) was given an object, `null` shape or a non-iterable instead of an array.

NG8004Angular

Angular: NG8004: No pipe found with name 'async' / 'date' / 'translate' — pipe not imported

The template uses a pipe Angular does not know — it is not imported into the component (standalone) or its module.

You provided 'undefined' where a stream was expectedAngular

RxJS: TypeError: You provided 'undefined' where a stream was expected. You can provide an Observable, Promise, ReadableStream, Array, AsyncIterable, or Iterable.

An RxJS operator (`switchMap`, `mergeMap`, `forkJoin`, `subscribe`) received `undefined` — a function forgot to `return` an Obser…

EmptyErrorAngular

RxJS: EmptyError: no elements in sequence (firstValueFrom / lastValueFrom on an empty Observable)

`firstValueFrom`, `lastValueFrom`, `first()` or `last()` waited for a value but the Observable completed without emitting.

TS2322TypeScript

TS2322: Type 'X' is not assignable to type 'Y'

You assigned a value whose type doesn’t match the declared type of the variable, property or return value.

404HTTP

HTTP 404 Not Found

The server can’t find anything at the requested URL.

Cannot GET /route on refreshAngular

Angular (production): Cannot GET /dashboard — 404 when refreshing or opening a deep link

The web server only knows `index.html`; a direct request to `/dashboard` is not a file, so it returns 404 instead of letting Angu…