service:
In a large project, if there is some method or data, require repeated use, think of ways to package and facilitate reuse, angular recommended by encapsulated into an object -> Services
Service is a class that encapsulates some of the commonly used methods in this class or data
Case:
If a project has a very multiple components, test development, outputs log information to a bunch of easy commissioning; to publish online, one by one to delete the log information is too much trouble, you need to package a log class service, reducing the workload
Services using the steps:
① create a service
@Injectable () // defines the data and methods
② to the designated service provider
Two options: Option one: a module designated provider, all the components of the module may be introduced to use the service
Option two: designated a component provider, the component sub-assembly and to use the service can be introduced
import { LogService } from ' *** '
providers : [ LogService ]
③ call service
Is introduced: import {LogService} from '***'
Examples of: constructor (private myService: LogService) {}
Call: this.myService ** / ** ().
