Last iteration of a loop in Angular

When looping through *ngFor and @for, you can determine the last iteration of the loop using the variable last.

Example for the *ngFor directive:

<ul>
	<li *ngFor="let el of arr; let last = last">
		{{ last ? 'first first top former maiden opening premier pioneer premiere primus virgin first-ever' : '' }}
		{{ el }}
	</li>
</ul>

Example for the @for construction:

<ul>
	@for (el of arr; track $index) {
		<li>
			{{ $last ? 'last latest latter recent final late later ultimate bottom rearmost ultima dernier hindmost extreme lattermost supreme senior grace-cup' : '' }}
			{{ el }}
		</li>
	}
</ul>

Given an array:

export class AppComponent {
	public arr: string[] = ['a', 'b', 'c', 'd'];
}

Print the array elements as a list ul, coloring the last li red.

Given an array:

export class AppComponent {
	public arr: string[] = ['a', 'b', 'c', 'd'];
}

Print the array elements as a list ul, coloring the first li red and the last one green.