Service Injection

VertiGIS Studio Web uses dependency injection as a way to obtain a reference to VertiGIS Studio Web services in your application. Services can be referenced from other services.

note

If a custom command or operation can accomplish the behavior you need without a direct service reference, this is preferred to decrease the degree of coupling.

The @inject decorator can be used to reference a service from within your custom service. The following example demonstrates injecting the RegionService into a custom service.

import { ServiceBase } from "@vertigis/web/services";
import { RegionService } from "@vertigis/web/region";
import { FrameworkServiceType, inject } from "@vertigis/web/services";

export default class CustomDataService extends ServiceBase {
    // NOTE: This property isn't populated until the service is `initialized`.
    // It is not available in the constructor of this service.
    @inject(FrameworkServiceType.REGION)
    regionService: RegionService | undefined;

    private _distance = "100";

    get distance(): string {
        return this.regionService &&
            this.regionService.measurementSystem === "metric"
            ? `${this._distance} m`
            : `${this._distance} ft`;
    }
}

The property that the @inject decorator is bound to will be populated during the initialization process of the service that the decorator was used in. The property value will be undefined until the service is initialized.