fuse-angular/src/app/modules/admin/apps/chat/new-chat/new-chat.component.ts

import { ChangeDetectionStrategy, Component, Input, OnDestroy, OnInit, ViewEncapsulation } from '@angular/core';
import { MatDrawer } from '@angular/material/sidenav';
import { Subject } from 'rxjs';
import { takeUntil } from 'rxjs/operators';
import { Contact } from 'app/modules/admin/apps/chat/chat.types';
import { ChatService } from 'app/modules/admin/apps/chat/chat.service';

@Component({
    selector       : 'chat-new-chat',
    templateUrl    : './new-chat.component.html',
    encapsulation  : ViewEncapsulation.None,
    changeDetection: ChangeDetectionStrategy.OnPush
})
export class NewChatComponent implements OnInit, OnDestroy
{
    @Input() drawer: MatDrawer;
    contacts: Contact[] = [];
    private _unsubscribeAll: Subject<any> = new Subject<any>();

    /**
     * Constructor
     */
    constructor(private _chatService: ChatService)
    {
    }

    // -----------------------------------------------------------------------------------------------------
    // @ Lifecycle hooks
    // -----------------------------------------------------------------------------------------------------

    /**
     * On init
     */
    ngOnInit(): void
    {
        // Contacts
        this._chatService.contacts$
            .pipe(takeUntil(this._unsubscribeAll))
            .subscribe((contacts: Contact[]) => {
                this.contacts = contacts;
            });
    }

    /**
     * On destroy
     */
    ngOnDestroy(): void
    {
        // Unsubscribe from all subscriptions
        this._unsubscribeAll.next();
        this._unsubscribeAll.complete();
    }

    // -----------------------------------------------------------------------------------------------------
    // @ Public methods
    // -----------------------------------------------------------------------------------------------------

    /**
     * Track by function for ngFor loops
     *
     * @param index
     * @param item
     */
    trackByFn(index: number, item: any): any
    {
        return item.id || index;
    }
}