How to get key from Observable? - json

Question

I am trying to read data from firebase using angular 2 and typescript
my code
export class DashboardComponent implements OnInit {
itemsRef: AngularFireList<any>;
items: Observable<any[]>;
constructor( afDatabase: AngularFireDatabase) {
this.itemsRef = afDatabase.list('/user_orders/louro');
this.items = this.itemsRef.valueChanges();
this.items.subscribe(val_2 => {
alert(val_2.keys());
val_2.forEach(function (value2) {
{
Object.keys(value2).forEach(function(k2) {
{
// k is key
let count = Object.keys( (value2[k2] )).length;
console.log("New order key "+k2);
for(let i=0;i<count;i++){
console.log(i+"=> "+JSON.stringify (value2[k2][i]));
}
}
});
}
})
});
}
ngOnInit() {
}
}
and on val_2 only contains
[
{
"-L7rtl2NesdOYVD4-bMs": [
{
"ads_show": false,
"brand": "",
"buttonLabel": "Add to cart",
"child": "fruits",
"decrn": "testing for demonstrate",
"key": "-L7rtXc0pMQhi1ClK-pP",
"mid": "fresh fruits",
"note": "",
"orderInfo": {
"message": "nil",
"methode": "cash on delivery",
"status": "nil",
"time": 1521356314040,
"time2": 1521356254115
},
"p_id": 73,
"p_name": "testing",
"position": 0,
"primary_key": "testinglouro",
"qty": {
"m_qty": 1,
"qty": 23,
"unite": "1kg",
"user_intput_qty": 2
},
"quantity_new": 2,
"querykey_shop_name_top": "louro_fruits",
"sellerName": "louro",
"sellonline": true,
"seo": {
"meta_descrption": "",
"meta_title": ""
},
"service": false,
"serviceMessage": "Please enter your complaint details",
"serviceTitle": "Service Requesting",
"shopname": "louro",
"shopview": false,
"summery": "nil",
"tags": "",
"top": "fruits",
"uid": "IG2SxH6Gcabr3QVLz9jE9Wwweh62",
"variants": [
{
"img_position": 0,
"prize": {
"mrp": 58,
"selling_prize": 45,
"tax": 0
},
"qty": {
"m_qty": 1,
"qty": 23,
"unite": "1kg",
"user_intput_qty": 2
},
"shipping": {
"minmumbuy": 0,
"s_cost": 0,
"s_dlts": ""
}
}
],
"variants_position": 0
}
]
}
]
And my database is
I need this key "4X2NpohlbUa3AA7ri6iHGNm2If93" .How to get that key ? I tried val_2.key
but it showing error "[ts] Property 'key' does not exist on type 'any[]'. Did you mean 'keys'?"
In java i am using below code and work fine dataSnapshot1.getKey();
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference(getResources().getString(R.string.user_orders)+"/"+
shop_name,getContext()));
myRef.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
// This method is called once with the initial value and again
// whenever data at this location is updated.
// MainAction.setDefaults("OpenCategories",dataSnapshot.toString(),getActivity());
if (dataSnapshot.hasChildren()) {
for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
orderDetails1 = null;
orderDetails1 = new OrderDetails();
if (dataSnapshot1.hasChildren()) {
int id = -1;
for (DataSnapshot dataSnapshot2 : dataSnapshot1.getChildren()) {
id = id + 1;
if (dataSnapshot2.hasChildren()) {
int productid = -1;
for (DataSnapshot dataSnapshot3 : dataSnapshot2.getChildren()) {
productid = productid + 1;
if (dataSnapshot3.hasChildren()) {
orderDetails1.productmillaList.add(dataSnapshot3.getValue(Productmilla.class));
}
orderDetails1.productmillaList.get(productid).setPosition(Integer.parseInt(dataSnapshot3.getKey()));
orderDetails1.productmillaList.get(productid).setId(dataSnapshot2.getKey());
// Log.d("key2",dataSnapshot2.getKey()+" "+productid);
}
}
//orderDetails1.productmillaList.get(id).setId(dataSnapshot2.getKey());
}
}
orderDetails1.key = dataSnapshot1.getKey();
orderDetails.add(orderDetails1);
}
getaddress(orderDetails);
} else mProgressBar.setVisibility(View.GONE);
}
#Override
public void onCancelled(DatabaseError error) {
// Failed to read value
mProgressBar.setVisibility(View.GONE);
Log.w("dd", "Failed to read value."+ error.getMessage());
}
});

Answer 1

Update :
According to the updated response data, you should access using Object.keys(val)[0] which gives the value for key "4X2NpohlbUa3AA7ri6iHGNm2If93", since it is the first key.
According to older response data :
Your val is an array.
This should work.
Object.keys(val[0]).forEach(function(k1) {
{
console.log("Key first : "+ k1);
});

Answer 2

In your JSON, val is an array.
Object.keys(val[0])
will give you the keys of the first element of that array, which is what you're after.

Answer 3

TO get the first key in the Object
Object.keys(val)[0]; //returns 'first key'
[https://stackoverflow.com/a/11509718/7458082][1]
To iterate through the object
Object.keys(obj).forEach(function(key,index) {
// key: the name of the object key
// index: the ordinal position of the key within the object
});
[https://stackoverflow.com/a/11509718/7458082][1]