Answers for "what is array components in angular"

ngfor

<li *ngFor="let item of items; index as i; trackBy: trackByFn">...</li>

represent array items angular

//for 
<div *ngFor='let [data] of [dataArray]; let i=index;'>
  <h2> {{i}} {{data.title}} </h2>
  <img src='{{data.image}}' />
  </div>   
  //the data contained in an array will be displayed element by element
  //similar to the function .map() in React