How can i store firebase data to json in local - node.js

Question

In my case I got the data from firestore now how can I save it to
serversettings.json:
var temp = {}
let query = db.collection('guilds')
let data = query.get().then(snapshot => {
snapshot.forEach(doc => {
console.log(doc.id, '=>',doc.data());
})
so I get the output as:
637301291068030997 => { welcomeChannelID: '<#648968505160630285>',
guildMemberCount: 4,
guildOwnerID: '348832732647784460',
guildOwner: 'Ethical Hacker',
prefix: '.',
guildID: '637301291068030997',
guildName: 'test server 3' }
and this:
GUqGqFanJuN7cRJx4S2w => {}
I need to save that data to serversettings.json
await fs.writeFile ("../serversettings.json", JSON.stringify(temp), function(err) {
if (err) throw err;
console.log('done');
})
here temp is variable where multiple data is stored like a:{},b:{}....
i tried var temp = {} temp.table = [] and then temp.table.push(doc.id, ':',doc.data())
but i get empty output so what can i do to get that expected output ?
also, adding to that how can I update the values if that object is already present in JSON will the above function work the same will it override the same value or delete all other values example update prefix from. to, then await fs.writeFile ("../serversettings.json", JSON.stringify(temp),..... so the temp field has a value of only guild id and that field prefix will it update the only prefix and not delete anything else in that array?
HERE is the code that added stuff to temp variable
var temp = {}
temp.guilds = [] // after some lines
snapshot.forEach(doc => {
console.log(doc.id, '=>',doc.data()); // output is above this code
temp.guilds.push(doc.id = doc.data()) // output is below this code
})
Above codes output
{ guilds:
[ { guildID: '637301291068030997', // here missing doc.id field
guildName: 'test server 3',
welcomeChannelID: '-',
guildMemberCount: 4,
guildOwnerID: '348832732647784460',
guildOwner: 'Ethical Hacker',
prefix: '.' },
{} // this missing thing before {} is (some number) also bracket is empty by the way so no worries
]
}

Answer 1

A fast solution for your issue would be to replace
let data = query.get().then(snapshot => {
with
await query.get().then(snapshot => {
so that your temp object can be filled before the program proceeds to save the file.
I haven't used writeFile yet, but here's what its documentation says:
When file is a filename, asynchronously writes data to the file, replacing the file if it already exists.
I don't think your object will be so large that a complete overwrite would be a problem, unless it's changing very often. In that case, I guess you'd have to use a different method that can support an offset, so that you can write only what has changed, but that seems like a real overkill.
Regarding the format of your JSON file, I think what you're trying to do is this:
var temp = {};
temp.guilds = {};
snapshot.forEach(doc => {
console.log(doc.id, '=>', doc.data());
temp.guilds[doc.id] = doc.data();
});

Answer 2

i`m not sure , but firebase has method to convert data from object to JSON, so i think this solution should work
let query = db.collection('guilds')
let data = query.get().then(snapshot => {
let temp = snapshot.toJSON()
await fs.writeFile ("../serversettings.json", temp, function(err) {
if (err) throw err;
console.log('done');
})
})