Error map
Port 4200 is already in use Angular CLI: Port 4200 is already in use. Use '--port' to specify a different port
Angular · layer 1, On your device
Centre: this error. First ring: errors it is linked with (8). 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 (8)
Error: listen EACCES: permission denied 0.0.0.0:80
Node isn’t allowed to bind that port — ports below 1024 need root on Linux/macOS, and some Windows ports are reserved.
Angular CLI: [HPM] Error occurred while proxying request localhost:4200 to http://localhost:3000 [ECONNREFUSED]
The `ng serve` dev proxy cannot forward your API call — it was not enabled, the path does not match, or the target server is down.
Angular CLI: zsh: command not found: ng / 'ng' is not recognized as an internal or external command
The Angular CLI is not installed globally or its folder is not on your PATH.
Angular CLI: Node.js version v16.20.2 detected. The Angular CLI requires a minimum Node.js version of v18.19.1
Your Node.js is older (or newer, unsupported) than the Angular CLI version needs.
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: Repository is not clean. Please commit or stash any changes before updating.
`ng update` refuses to run because git has uncommitted changes; it wants every migration to be a reviewable diff.
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.
Two steps away (20)
Error: listen EADDRINUSE: address already in use :::3000
Another process is already listening on that port.
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
The docker CLI can’t talk to the Docker engine — it isn’t running, or your user can’t access the socket.
Docker: Bind for 0.0.0.0:80 failed: port is already allocated
Another container or host process already publishes that host port.
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: HttpErrorResponse — Http failure response for (unknown url): 0 Unknown Error (status 0)
`HttpClient` got no HTTP response at all: the request was blocked (CORS), failed at network level, or the server is unreachable —…
Angular: Http failure response for http://…/api/x: 404 Not Found (HttpErrorResponse)
The API answered 404 — the URL is wrong (base URL, path or id), or the proxy/rewrite does not forward the request.
bash: command not found
The shell can’t find an executable with that name in any directory on your PATH.
npm ERR! enoent ENOENT: no such file or directory, open '/path/package.json'
npm ran in a directory without a package.json.
Angular: Error: The Angular Compiler requires TypeScript >=5.4.0 and <5.6.0 but 5.7.2 was found instead
The installed TypeScript version is outside the range your Angular version supports.
npm WARN EBADENGINE Unsupported engine / The engine "node" is incompatible with this module
A package requires a different Node.js version than the one you’re running.
Angular: npm ERR! ERESOLVE could not resolve — Conflicting peer dependency: @angular/core@"^16.0.0" (after ng update / ng add)
A package in your project requires an older Angular version than the one you are installing, so npm refuses the upgrade.
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 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: 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…
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: 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…
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