angular - Uncaught TypeError: Cannot set property 'length' of null at VirtualScroll.readUpdate -


i using simple ion-list ngfor display items in list in ionic 3 & working fine. used virtual scroll ion-list & getting following error:

uncaught typeerror: cannot set property 'length' of null @ virtualscroll.readupdate

code snippet:

 <ion-list [virtualscroll]="anarray" approxitemheight="50px">         <div *virtualitem="let arrayitem">     //other code  array declaration:      public anarray: any[];  in constructor:     this.anarray = [];  after network response:     this.anarray = data.result;


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