I would flip-flop your button
and div
:
<div *ngFor="let item of items">
<button *ngIf="(item.data.type == 1)">{{item.data.name}}</button>
</div>
This way only buttons get created for valid items.
You can also use a function in your component:
<button *ngFor="let item of filterItemsOfType('1')">{{item.data.name}}</button>
Where your component has a function:
filterItemsOfType(type){
return this.items.filter(x => x.data.type == type);
}