src/app/pages/details/components/statement-details/statement-details.component.ts

/********************************************************************************
 * Copyright (c) 2020 Contributors to the Eclipse Foundation
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0
 *
 * SPDX-License-Identifier: EPL-2.0
 ********************************************************************************/

import {Component, OnDestroy, OnInit} from "@angular/core";
import {select, Store} from "@ngrx/store";
import {Observable, Subscription} from "rxjs";
import {filter, switchMap} from "rxjs/operators";
import {queryParamsIdSelector} from "../../../../store/root/selectors/query-params.selectors";
import {IStatementEntity} from "../../../../store/statements/model/IStatementEntity";
import {fetchStatementDetailsAction} from "../../../../store/statements/statements.actions";
import {statementSelector} from "../../../../store/statements/statements.selectors";

@Component({
    selector: "app-statement-details",
    templateUrl: "./statement-details.component.html",
    styleUrls: ["./statement-details.component.scss"]
})
export class StatementDetailsComponent implements OnInit, OnDestroy {

    public id$: Observable<number>;

    public statement$: Observable<IStatementEntity>;

    private subsription: Subscription;

    public constructor(private readonly store: Store) {
        this.id$ = this.store.pipe(select(queryParamsIdSelector));

        this.statement$ = this.id$.pipe(
            switchMap((id) => this.store.pipe(select(statementSelector, {id})))
        );
    }

    public ngOnInit(): void {
        this.subsription = this.id$
            .pipe(filter((id) => id != null))
            .subscribe((id) => this.store.dispatch(fetchStatementDetailsAction({id})));
    }

    public ngOnDestroy(): void {
        if (this.subsription != null) {
            this.subsription.unsubscribe();
        }
    }

}