Firestore query: getting data and storing it into an variable . How to use that variable in cloud functions?

Question

To get a data from the firestore I queried a document and get that data into variable. Now, I need to use that variable in other part of the code. when I am using that variable it does not get any data . How to resolve these error.

var d1;
                    var getdata = respond.get()
                                    .then(doc =>{
                                    if(!doc.exists){
                                    console.log('No such document');
                                    }else{
                                    console.log('Document data:', doc.data());
                                     d1 = doc.data();// In d1 I am  not getting the data of that document 
                                    }
                                    }).catch(err => {
                                    console.log('Error getting documnet', err);
                                    });

Here in for loop, I am using the d1 variable. But it is not executing these for loop

for(var k in d1){
                     var p = d1[k].PhoneNumber;
                     let rph = respond.where(receiverph ,"==", p)
                                    .set({
                                    Status : status
                                    });
                                    let payload = {
                                        notification : {
                                        title: "Message",
                                        body: msg,
                                         sound:"default",
                                         }
                                    };
                                    console.log(payload);
                                    return admin.messaging().sendToDevice(token,payload).then((response) =>{
                                    console.log(token);
                                    console.log("Successfully sen notification");
                                    }).catch(function(error){
                                    console.warn("Error sending notification",error);
                                    });


                     }


                    });

In d1 the data is

{ Invite2: { PhoneNumber: 917893659558, Amount: 33 },
  Invite1: { PhoneNumber: 917799266509, Amount: 33 },
  Invite3: { Amount: 33, PhoneNumber: 918639146409 } 
}

Is this all your code? If so, it’s because the for loop actually executes before you assign the data to d1. Since get operations are asynchronous. — Vincent, Mar 19 '18 at 22:31
Yaa This the code I have written Iam not getting the data in d1 — Lahari Areti, Mar 20 '18 at 03:44
Yea it’s because get is asynchronous. Try placing a log statement right above the for loop. You’ll see it logs before the document is fetched. — Vincent, Mar 20 '18 at 04:14
I checked it , it prints undefined how to resolve this problem — Lahari Areti, Mar 20 '18 at 05:09

score 1 · Answer 1 · answered May 07 '18 at 13:35

Use Promisse.all

let promise = [];
let all = [];
for(var k in d1){
    var p = d1[k].PhoneNumber;
    let rph = respond.where(receiverph ,"==", p)
        .set({ Status : status });
        let payload = {
            notification : {
            title: "Message",
            body: msg,
                sound:"default",
                }
        };
        console.log(payload);
        return admin.messaging().sendToDevice(token,payload).then((response) =>{
        console.log(token);
        console.log("Successfully sen notification");
        }).catch(function(error){
        console.warn("Error sending notification",error);
        });
    }
    promise.push(rhp);
});

Promise.all(promise).then((data)=>{
     data.forEach(query => {
       query.forEach(res=>{
          all.push(res.data());
     })
})

score 0 · Answer 2 · answered Mar 20 '18 at 05:23

When you get a document with .get, the document has to be fetched from the database. Therefore this operation is asynchronous and you must wait until the document is received before you can iterate on its data. In short, it should look something like the following:

some_doc_ref.get().then(doc => {
  if (doc.exists) {
    var d1 = doc.data();

    for(var k in d1) {
      //...
    }
  }
});

Hope that helps.

Firestore query: getting data and storing it into an variable . How to use that variable in cloud functions?

2 Answers2

Linked