Storage

Daffodil abstracts the storage layer behind the DaffPersistenceService interface. A number of different services implement this interface and suit different use cases.

Services

Service	Usage
`DaffLocalStorageService`	Uses `localStorage` to implement persistence. It's appropriate for browser environments.
`DaffMemoryStorageService`	Stores items in-memory. It's appropriate for testing environments or when true persistence is not desired.
`DaffErrorStorageService`	Always throws an error when it's invoked. It's appropriate for server environments such as SSR where storage mechanisms are not available.
`DaffNoopStorageService`	Never performs any actions and always returns `undefined`.

Environment specific storage services

The storage service used can be configured by providing the DaffPersistenceServiceToken injection token. The following example demonstrates how to provide appropriate services based on the current environment.

import { PLATFORM_ID } from '@angular/core';
import { isPlatformBrowser } from '@angular/common';
import {
  DaffPersistenceServiceToken,
  DaffLocalStorageService,
  DaffErrorStorageService
} from '@daffodil/core';

@NgModule({
  ...,
  providers: [
    {
      provide: DaffPersistenceServiceToken,
      deps: [PLATFORM_ID],
      useFactory: (platformId: string) => isPlatformBrowser(platformId)
        ? new DaffLocalStorageService(platformId)
        : new DaffErrorStorageService()
    }
  ]
})
class AppModule {}