[4.0.0-beta.18] Virtualscroll gives "template for virtual item was not provided"

[henkkelder]

Bug Report

Ionic version:
[x] 4.x

Current behavior:
Error in console: Error: template for virtual item was not provided. No items or headers are shown.

Expected behavior:
Should show header and items.

Steps to reproduce:

Related code:

<ion-content>
    <ion-virtual-scroll *ngIf="hasLoaded" [items]="programmaOnderdelen" [headerFn]="HeaderFn" approxItemHeight="68px" approxHeaderHeight="30px">
        <ion-item-divider *virtualHeader="let header">
            {{ header }}
        </ion-item-divider>
        <ion-item *virtualItem="let po" href="#" (click)=" onHeaderClick(po)" lines="none" >
            <ion-avatar category-menu={{po.categorie}}>
                <img [src]="po.cat.pict" />
            </ion-avatar>
            <ion-label>
                <div class="topline" [ngStyle]="{color : po.sublocatie.hoofdlocatie.bcolor}">
                    <span>{{po.aanvangsDt * 1000 | date: "EEE H:mm" }}</span>
                    <span *ngIf="po.eindDt"> - {{po.eindDt * 1000 | date: "H:mm" }}</span>
                    <span style="padding-left:10px;">{{po.sublocatie.hoofdlocatie.naam}}</span>
                </div>
                <div class="titleline">
                    <span class="title">{{po.titel}}</span>
                </div>
            </ion-label>
        </ion-item>
    </ion-virtual-scroll>
</ion-content>

Other information:
In virtual-scroll.js, routine getComponent expects a numeric argument 'type'. But it is called with a string argument being 'item', 'header' or 'footer'. This results in an exception being thrown a line 41.

Ionic info:

Ionic:

   ionic (Ionic CLI)             : 4.5.0 (C:\Users\henkkelder\AppData\Roaming\npm\node_modules\ionic)
   Ionic Framework               : @ionic/angular 4.0.0-beta.18
   @angular-devkit/build-angular : 0.10.7
   @angular-devkit/schematics    : 7.1.3
   @angular/cli                  : 7.1.3
   @ionic/angular-toolkit        : 1.2.0

Cordova:

   cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
   Cordova Platforms     : android 7.1.2, browser 5.0.4
   Cordova Plugins       : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 2.2.5, (and 18 other plugins)

System:

   Android SDK Tools : 26.1.1 (C:\Users\henkkelder\AppData\Local\Android\Sdk)
   NodeJS            : v8.11.4 (C:\Program Files\nodejs\node.exe)
   npm               : 6.4.1
   OS                : Windows 10

[manucorporat]

was it working in beta.17?

[henkkelder]

Yes it was.
Although on IOS the virtualScroller needed a 'manual scroll' to show anything. On Android it worked with some minor glitches.

I have modified getComponent on my own system so the switch checks for the stringvalues and then it works again. I cannot find why the cell.type changed from numeric value to string.

[manucorporat]

@henkkelder you are right! it's a bug, i am working in a fix a new tests for angular.
Thanks for the issue report!

[ionitron-bot]

Thanks for the issue! This issue is being locked to prevent comments that are not relevant to the original issue. If this is still an issue with the latest version of Ionic, please create a new issue and ensure the template is fully filled out.