Error map
NG8001 Angular: NG8001: 'app-item' is not a known element — verify that it is included in the component's imports
Angular · layer 1, On your device
Centre: this error. First ring: errors it is linked with (12). 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 (12)
Angular: NullInjectorError: No provider for X!
Angular’s dependency injection couldn’t find a provider for a service/token the component needs.
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: 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.
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 `@…
Angular: NG8113: NgIf is not used within the template of AppComponent — unused standalone import
A standalone component lists a directive, pipe or component in `imports` but never uses it in its template.
Angular Material: Error: mat-form-field must contain a MatFormFieldControl
A `` has no Material input inside, or the module that provides `matInput`/`mat-select` is not imported.
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: NG0301: Export of name 'x' not found! (template variable #x="exportAs")
A template variable asks for a directive by `exportAs` name, but no directive with that export is on the element at runtime.
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…
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.
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.
Two steps away (18)
InvalidOperationException: Unable to resolve service for type 'X' while attempting to activate 'Y'
ASP.NET Core’s dependency injection container can’t build Y because one of its constructor dependencies (X) was never registered.
UnsatisfiedDependencyException / NoSuchBeanDefinitionException: No qualifying bean of type 'X' available
Spring couldn’t find (or choose) a bean to inject.
The dependencies of some of the beans in the application context form a cycle
Two or more Spring beans depend on each other through constructors, and Spring Boot 2.6+ forbids cycles by default.
Warning: A component is changing an uncontrolled input to be controlled
An input’s `value` started as `undefined` (uncontrolled) and later became a defined value (controlled), or vice versa.
django.template.exceptions.TemplateDoesNotExist: app/page.html
Django searched all template directories and couldn’t find that template.
Contact Form 7: There was an error trying to send your message. Please try again later.
The form submitted, but wp_mail() failed to send — the server can’t send mail or the mail settings are wrong.
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: NG01203: No value accessor for form control with name: 'x' (ControlValueAccessor missing)
A form directive (`formControlName`, `ngModel`) is on an element or component that Angular cannot read/write values from.
Angular: NG01050: formControlName must be used with a parent formGroup directive
`formControlName` is used outside any `[formGroup]` — the control has no form to belong to.
Angular: NG02100: InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe'
The `async` pipe received a plain object or array instead of an Observable or Promise.
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…
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.
Angular: NG01352: If ngModel is used within a form tag, either the name attribute must be set or the form control must be defined as 'standalone'
An `[(ngModel)]` input sits inside a `` but has no `name`, so Angular cannot register it as a form control.
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…
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.
Angular tests: Component 'X' is not resolved: templateUrl: ./x.component.html — Did you run and wait for 'resolveComponentResources()'?
A test created a component whose external template was not compiled yet — `compileComponents()` was not called/awaited, or the te…
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…
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