Angular io (4) *ngFor first and last

Inside the ngFor you have access to several variables:

• index: number: The index of the current item in the iterable.
• first: boolean: True when the item is the first item in the iterable.
• last: boolean: True when the item is the last item in the iterable.
• even: boolean: True when the item has an even index in the iterable.
• odd: boolean: True when the item has an odd index in the iterable.

So:

<md-expansion-panel *ngFor="let item of items; first as isFirst"    *ngClass="{ 'first' : isFirst }">  <content></content></md-expansion-panel>

Documentation at https://angular.io/api/common/NgForOf gives this example:

<li *ngFor="let user of userObservable | async as users; index as i; first as isFirst">   {{i}}/{{users.length}}. {{user}} <span *ngIf="isFirst">default</span></li>

This how you can do it :

<md-expansion-panel *ngFor="let item of items; let first = first;       let last = last" [ngClass]="{ 'first' : first }">   <content></content> </md-expansion-panel>

NgFor provides several exported values that can be aliased to local variables:

• index will be set to the current loop iteration for each templatecontext so it start from 0.

• first will be set to a boolean value indicating whether the item isthe first one in the iteration.

• last will be set to a boolean value indicating whether the item isthe last one in the iteration.

• even will be set to a boolean value indicating whether this item hasan even index.

• odd will be set to a boolean value indicating whether this item hasan odd index.

for more information : NgFor-directive 🚀🚀

a complete example

<div    *ngFor="let n of items; let itemsCount = count;let idx = index , let isOdd = odd;let first = first ;let last = last;">    {{n}} ,    {{itemsCount}} ,    {{idx}} ,    odd 👉 {{isOdd}} ,    first 👉 {{first}} ,    last 👉 {{last}}</div>

demo 🚀