Updating a user concurrently in mongoose using model.save() throws error - node.js

Question

I am getting a mongoose error when I attempt to update a user field multiple times.
What I want to achieve is to update that user based on some conditions after making an API call to an external resource.
From what I observe, I am hitting both conditions at the same time in the processUser() function
hence, user.save() is getting called almost concurrently and mongoose is not happy about that throwing me this error:
MongooseError [ParallelSaveError]: Can't save() the same doc multiple times in parallel. Document: 5ea1c634c5d4455d76fa4996
I know am guilty and my code is the culprit here because I am a novice. But is there any way I can achieve my desired result without hitting this error? Thanks.
function getLikes(){
var users = [user1, user2, ...userN]
users.forEach((user) => {
processUser(user)
})
}
async function processUser(user){
var result = await makeAPICall(user.url)
// I want to update the user based on the returned value from this call
// I am updating the user using `mongoose save()`
if (result === someCondition) {
user.meta.likes += 1
user.markModified("meta.likes")
try {
await user.save()
return
} catch (error) {
console.log(error)
return
}
} else {
user.meta.likes -= 1
user.markModified("meta.likes")
try {
await user.save()
return
} catch (error) {
console.log(error)
return
}
}
}
setInterval(getLikes, 2000)

Answer 1

There are some issues that need to be addressed in your code.
1) processUser is an asynchronous function. Array.prototype.forEach doesn't respect asynchronous functions as documented here on MDN.
2) setInterval doesn't respect the return value of your function as documented here on MDN, therefore passing a function that returns a promise (async/await) will not behave as intended.
3) setInterval shouldn't be used with functions that could potentially take longer to run than your interval as documented here on MDN in the Usage Section near the bottom of the page.
Hitting an external api for every user every 2 seconds and reacting to the result is going to be problematic under the best of circumstances. I would start by asking myself if this is absolutely the only way to achieve my overall goal.
If it is the only way, you'll probably want to implement your solution using the recursive setTimeout() mentioned at the link in #2 above, or perhaps using an async version of setInterval() there's one on npm here