get collections in firebase code example
Example 1: how to query in firestore
db.collection("cities").where("capital", "==", true)
.get()
.then(function(querySnapshot) {
querySnapshot.forEach(function(doc) {
// doc.data() is never undefined for query doc snapshots
console.log(doc.id, " => ", doc.data());
});
})
.catch(function(error) {
console.log("Error getting documents: ", error);
});
Example 2: multiple query at once in firebase
function doSomething(...){
let result1 = [];
let result2 = [];
admin.firestore().collection('...').where('some condition').get()
.then((results: any)=>{
results.forEach((element: any)=>{
if(some other condition){
result1.push(element);
}
})
.catch((error: any)=>{//log the error});
admin.firestore().collection('...').where('yet another condition').orderBy(...).get()
.then((results: any)=>{
results.forEach((element: any)=>{
result2.push(func(element)) //func is some manipulation
})
.catch((error: any)=>{//log the error});
return makeCalculation(result1, result2);
}