I have a function that adds information to the database. I would like to check if the data already exists and if it does, return the function and not continue. Im not sure whats going on. Every time i run the function it returns and cancels.
#How do i check if data already exists in mongodb before writing it?
teal mist
icy maple
well the first thing i can see there is that your guard clause isn't awaited
idk if that's an issue personally since i'm not all that on mongoose fyi, but based on your code a little further down i'm guessing it's async
since you're using find as opposed to findOne the return type should be array-like
if it's array-like, then if something isn't found, it'll be returning an empty array
and js being js, an empty array is truthy
try changing it to findOne and test whether it's === null
(truthy is a problem for you since even if mongoose doesn't find any matching User documents, it will still evaluate to true)
teal mist
well the first thing i can see there is that your guard clause isn't awaited
Whats a gaurd clause?
teal mist
since you're using find as opposed to findOne the return type should be array-li...
I need it to return true or false. Is that a problem?
icy maple
Whats a gaurd clause?
it's what you've done. alternative to if/else, you're checking if something is true and then returning to exit the function
teal mist
try changing it to findOne and test whether it's === null
Ill change it to findOne
icy maple
if (User.find[...]) but you probably want to await the result of the find / findOne
teal mist
did you await?
No i didnt
tbh im not very good at using async and await
ill try to set it up and ill show you what i did
icy maple
pls copy and paste instead of screenshots when sharing code
teal mist
Alright ill do that
icy maple
it's hard to help if i can't quote parts
teal mist
// before adding to the database, see if it already exists
if (await User.findOne( { name: name} )){
console.log("not adding to the database")
return;
}
const user = await User.create({
name: name,
email: email
})
// user.name = "Dajuan"
await user.save()
console.log(user);
}
Yeah i do
It runs the function but skips over it
so await makes it stay and wait for a result
icy maple
sorta. it was actually not skipping over it, but the opposite, but for a related reason
basically a promise is an object that eventually becomes a value right
teal mist
basically a promise is an object that eventually becomes a value right
I dont fully understand asyncronous code but sure
Im trying to learn it
icy maple
well, if you say if ({}) then you get true
teal mist
Yeah
icy maple
because it's an empty object, and according to js, empty objects == true
a promise is an object, so it's always == true
teal mist
Yeah
icy maple
so your code before was saying if (mongodbstuff)
teal mist
mhmm
icy maple
but because you weren't awaiting, it was evaluating the object it had - which was a promise - which was true. so it was always entering the block
teal mist
Ohhh
icy maple
by using await, like you said, it waits for the final value before checking whether it's true or false
teal mist
Ohh yeah
icy maple
the other half was with the other change we talked about, findOne
before when you were using find, because find can find multiple records, it returns them in an array-like structure
so even if you awaited it, if you used find, then the empty array which got returned would have still == true because in js empty arrays == true
teal mist
so even if you awaited it, if you used find, then the empty array which got retu...
Yeah your right
icy maple
two separate problems which arrived in the same bug basically
icy maple
np
teal mist
Do you know how to use compass?
icy maple
alas nope
icy maple
no no i said alas lol
teal mist
alas like, unfortunately
Do you know anyone who could help me with mongoose and compass?
icy maple
ive never seen anybody say that
i couldn't tell that english wasn't your first language haha
afraid not probably worth a separate thread
also be specific about what your problem is since it might be a generic-enough problem that general knwoeldge can solve it
teal mist
i couldn't tell that english wasn't your first language haha
Im from the US so it is lmao
teal mist
also be specific about what your problem is since it might be a generic-enough p...
Yeah
im new to this
Mongodb is just confusing
icy maple
Im from the US so it is lmao
y'all don't say alas? maybe a uk thing then
teal mist
Yeah its def a UK thing
Ill create a new thread for it
im gonna delete this
tysm tho
icy maple
don't delete it
teal mist
Oh okay i wont
icy maple
leave it in case someone has a similar problem