layout.component.html

<div class="layout-container" #layoutContainer [fxLayout]="layoutAlignment">
  <ng-container *ngTemplateOutlet="alwaysVisiblePagePosition === 'top' || alwaysVisiblePagePosition === 'left' ?
    alwaysVisiblePageView :
    scrollPagesView"></ng-container>
  <ng-container *ngTemplateOutlet="alwaysVisiblePagePosition === 'bottom' || alwaysVisiblePagePosition === 'right' ?
    alwaysVisiblePageView :
    scrollPagesView"></ng-container>
</div>

<ng-template #alwaysVisiblePageView>
  <div *ngIf="alwaysVisiblePage"
       class="page-container"
       [fxFlex]="pageExpansion">
  <div appHideFirstChild [hideFirstChild]="hidePageLabels">
    <div class="mat-tab-label">{{'alwaysVisiblePage' | translate}}</div>
      <app-page [parentArrayIndex]="alwaysVisibleUnitPageIndex"
                [parentForm]="parentForm"
                [pagesContainer]="layoutContainer"
                [page]="alwaysVisiblePage">
      </app-page>
    </div>
  </div>
</ng-template>

<ng-template #scrollPagesView>
  <ng-container *ngIf="hasScrollPages">
    <ng-container *ngTemplateOutlet="scrollPageMode === 'separate' ?
      scrollPagesSeparatedView :
      scrollPagesScrolledView"></ng-container>
  </ng-container>
</ng-template>

<ng-template #scrollPagesSeparatedView>
    <mat-tab-group appHideFirstChild
                   [hideFirstChild]="hidePageLabels"
                   class="tab-page-container"
                   [fxFlex]="pageExpansion"
                   mat-align-tabs="start"
                   [(selectedIndex)]="selectedIndex"
                   (selectedIndexChange)="onSelectedIndexChange($event)">
      <ng-container *ngFor="let page of pages; let i = index">
        <mat-tab *ngIf="!page.alwaysVisible"
                 label="{{'pageIndication' | translate: {index: playerPageIndices[i] + 1} }}">
          <app-page [parentArrayIndex]="i"
                    [parentForm]="parentForm"
                    [pagesContainer]="layoutContainer"
                    [page]="page">
          </app-page>
        </mat-tab>
      </ng-container>
    </mat-tab-group>
</ng-template>

<ng-template #scrollPagesScrolledView>
  <div class="page-container"
       [ngClass]="{'concat-scroll-snap' : playerConfig.pagingMode === 'concat-scroll-snap'}"
       [fxFlex]="pageExpansion">
    <div fxLayout="column">
      <ng-container *ngFor="let page of pages; let i = index">
        <div *ngIf="!page.alwaysVisible"
             [ngClass]="{'concat-scroll-snap-align' : playerConfig.pagingMode === 'concat-scroll-snap'}"
             appHideFirstChild
             [hideFirstChild]="hidePageLabels"
             appScrollIndex
             [selectedIndex]="selectedIndex"
             [index]="playerPageIndices[i]">
          <div class="mat-tab-label">
            {{'pageIndication' | translate: {index: playerPageIndices[i] + 1} }}
          </div>
          <app-page [parentArrayIndex]="i"
                    [parentForm]="parentForm"
                    [pagesContainer]="layoutContainer"
                    [page]="page"
                    (selectedIndexChange)="onSelectedIndexChange($event)">
          </app-page>
        </div>
      </ng-container>
    </div>
  </div>
</ng-template>