FIREBASE getting document data

Tags: , , , ,

I’m making an app and trying to get product data by it’s id inside a modal in ionic 4. I’m using typescript to do it but without luck. Because de calls to firebase are asynchronous i cannot get the data that is held in firebase and also because i’m new to subject i cannot figured out the proper way to write the code. I read about how to do it but i’m having a hard time to achieve it.

Here is my function that tries to grab product data from firebase. It always logs empty on console.log(‘todo’, todo).

async editProduct(id) {
        const getTodo = docRef => {
            setTimeout(() => {
                docRef = this.afs.collection("products").doc(id);
                docRef.get().subscribe((doc) => {
                    if (doc.exists) {
                        let data =;
                        return data;
                    } else {
                        console.log("No document.");
                        return false;
            }, 2000)

        getTodo(todo => {
            console.log('todo', todo)

        const modal = await this.modalCtrl.create({
            component: AdminProductPage,
            'id': id,
        await modal.present();


There is something wrong with your “getTodo”. Probable you are logging empty data with your code, I can give you the proper functional example:


editProduct() {
        .subscribe(data => {
          myData = data

getData() {
    console.log(this.myData) // You will log it twice with this line


docRef.get().then((doc) => {
    if (doc.exists) {
        console.log("Document data:",;
    } else {
        // will be undefined in this case
        console.log("No such document!");
}).catch((error) => {
    console.log("Error getting document:", error);

Source: stackoverflow