[英]Call service method to provide other services within app.module.ts
I have a configuration service that provides a method called getConfiguration(): Observable <Configuration>
.我有一个配置服务,它提供了一个名为getConfiguration(): Observable <Configuration>
的方法。
In order to fill my external library, I would like to provide this method within app.module.ts
(I want to fill the InjectionToken, which is expected in the library).为了填充我的外部库,我想在app.module.ts
中提供此方法(我想填充库中预期的 InjectionToken)。
Now I wonder how I can/should call this logic in the providers block.现在我想知道如何/应该在提供程序块中调用此逻辑。
@NgModule({
declarations: [AppComponent],
imports: [
//...
],
providers: [
{
provide: MY_CONFIG,
useValue: ConfigurationService.getConfiguration(), // <--- won't work!
}
]
bootstrap: [AppComponent],
})
export class AppModule {}
Can you help me with that?你能帮我解决这个问题吗?
If your library expects the token to be Observable <Configuration>
, then you can use factory to provide the Observable value as follows:如果您的库希望令牌是Observable <Configuration>
,那么您可以使用工厂提供 Observable 值,如下所示:
More details on using factory provider: https://angular.io/guide/dependency-injection-providers#using-factory-providers有关使用工厂提供程序的更多详细信息: https://angular.io/guide/dependency-injection-providers#using-factory-providers
function configFactory(configService: ConfigurationService) {
return configService.getConfiguration();
}
...
providers: [
{
provide: MY_CONFIG,
useFactory: configFactory,
deps: [ConfigurationService]
}
]
...
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