• Overview
@angular/core

APP_ID

constant
stable

A DI token representing a string ID, used primarily for prefixing application attributes and CSS styles when ViewEncapsulation#Emulated is being used.

API

  const APP_ID: InjectionToken<string>;  

Description

A DI token representing a string ID, used primarily for prefixing application attributes and CSS styles when ViewEncapsulation#Emulated is being used.

The token is needed in cases when multiple applications are bootstrapped on a page (for example, using bootstrapApplication calls). In this case, ensure that those applications have different APP_ID value setup. For example:

bootstrapApplication(ComponentA, { providers: [ { provide: APP_ID, useValue: 'app-a' }, // ... other providers ... ]});bootstrapApplication(ComponentB, { providers: [ { provide: APP_ID, useValue: 'app-b' }, // ... other providers ... ]});

By default, when there is only one application bootstrapped, you don't need to provide the APP_ID token (the ng will be used as an app ID).

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