Unable to add array to firebase-firestore in reactjs? - arrays

Question

I am trying to send a list of arrays to Firestore using a variable called array_list but when I check my firebase console the array is present but the value inside of it is empty.
let array_list = [];
let user_id = localStorage.getItem("userId");
function add_data() {
let i = 0;
for(i;i<10;i++){
array_list.push(i);
}
}
add_data()
let db = firebase.firestore();
if (user_id !== null) {
var doc = db.collection("users").doc(user_id);
}
const sendHistData = () => {
console.log("Creating Database...");
doc
.set({
browsingHistory: array_list,
})
.then(() => {
console.log("Document successfully written!");
})
.catch((error) => {
console.log(error);
});
};
if(user_id!==null){
add_data();
sendHistData();
}
Here is the link to the full code
Here is the screenshot

Answer 1

The var "doc" seems to be undefined in your sendHistData function. Try refactoring the function:
let db = firebase.firestore();
const sendHistData = () => {
// if (!user_id) return null // user not logged in
const db = firebase.firestore().collection("users").doc(user_id)
console.log("Creating Database...");
doc
.set({
browsingHistory: array_list,
})
.then(() => {
console.log("Document successfully written!");
})
.catch((error) => {
console.log(error);
});
};
Also you are checking if user_id is null or not before calling the function so verifying that again inside of the function is redundant.