Angular para o valor da chave do loop
<div *ngFor="let item of testObject | keyvalue">
Key: <b>{{item.key}}</b> and Value: <b>{{item.value}}</b>
</div>
Fragile Falcon
<div *ngFor="let item of testObject | keyvalue">
Key: <b>{{item.key}}</b> and Value: <b>{{item.value}}</b>
</div>this.map.forEach((value: string, key: string) => {
console.log(key, value);
});