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I am trying to fetch the documents of a collection in my React-Native app but I dont know how to fetch them by ID (key). P.S: I dont have any field called unique id or id inside the document but as I have understood, the unique id is the auto-generated key when I create a document which stands as the name of that document (20 characters id).
This is how I fetch all the fields inside a document:
var ref = firebase.firestore().collection('discounts')
.orderBy('rest_id')
EDIT:
getDiscounts = () => {
try {
this.setState({
loading: true
})
var ref = firebase.firestore().collection('discounts')
.orderBy('rest_id')
.limit(this.state.limit)
ref.onSnapshot((querySnapshot => {
var discounts = querySnapshot.docs.map(document => document.data());
var lastVisibleDiscount = discounts[discounts.length - 1].rest_id;
this.setState({
discounts: discounts,
lastVisibleDiscount: lastVisibleDiscount,
loading: false,
});
}));
}
catch (error) {
console.log(error);
}
}
I am trying to fetch the documents of a collection in my React-Native app but I dont know how to fetch them by ID (key). P.S: I dont have any field called unique id or id inside the document but as I have understood, the unique id is the auto-generated key when I create a document which stands as the name of that document (20 characters id).
This is how I fetch all the fields inside a document:
var ref = firebase.firestore().collection('discounts')
.orderBy('rest_id')
EDIT:
getDiscounts = () => {
try {
this.setState({
loading: true
})
var ref = firebase.firestore().collection('discounts')
.orderBy('rest_id')
.limit(this.state.limit)
ref.onSnapshot((querySnapshot => {
var discounts = querySnapshot.docs.map(document => document.data());
var lastVisibleDiscount = discounts[discounts.length - 1].rest_id;
this.setState({
discounts: discounts,
lastVisibleDiscount: lastVisibleDiscount,
loading: false,
});
}));
}
catch (error) {
console.log(error);
}
}
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edited Dec 23, 2019 at 18:36
asked Dec 23, 2019 at 17:55
user12396958user12396958
2 Answers
Reset to default 6To print the keys of the documents in the collection in the order of the value of their rest_id
field, you can do something like this:
firebase.firestore().collection("discounts").orderBy('rest_id').get().then(function(querySnapshot) {
querySnapshot.forEach(function(doc) {
console.log(doc.id);
});
});
This is an almost literal copy of the code in the documentation on getting all documents from a collection, so I remend spending some time there.
You can use (using await/async)
const ref = await ref.get()
It will have an array called docs that you can map over to get the id and data of the document:
const data = ref.docs.map(doc => {return {id: doc.id, data: doc.data()} })
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