NgRX State Machine - component state service

component-state.service.ts

// the component uses an injected componentStateService to register its state transitions

this._componentStateService.addComponentStates(componentStates);

// the component state service is reasonably simple and just maintains a lookup object of all the registered
// state transitions, and also has methods for cleaning these up when components are destroyed

@Injectable()
export class ComponentStateService {
    public componentStates: any = {};

    constructor(private _store: Store<RootState>) {
        Guard.notNothing(_store, '_store');
    }

    public addComponentStates(componentStateData: any) {
        this.deleteComponentState(componentStateData.name);
        forOwn(componentStateData.states, (value: any, key: string) => {
            if (!this.componentStates[key]) {
                this.componentStates[key] = {};
            }
            if (!this.componentStates[key][componentStateData.name]) {
                if (componentStateData.id) {
                    value.id = componentStateData.id;
                }
                this.componentStates[key][componentStateData.name] = value;
            }
        });
    }

    public removeComponentStates(componentName: string) {
        forOwn(this.componentStates, (value: any, key: string) => {
            if (value[componentName]) {
                delete this.componentStates[key][componentName];
            }
            if (isEmpty(this.componentStates[key])) {
                delete this.componentStates[key];
            }
        });
        this.deleteComponentState(componentName);
    }

    public updateComponentState(componentName: string, uiState: ComponentStates) {
        this._store.dispatch(new UpdateComponentStateAction({ componentName, uiState }));
    }

    public deleteComponentState(componentName: string) {
        this._store.dispatch(new DeleteComponentStateAction({ componentName }));
    }
}