this is what happens when I console.log()
this is what happens when I return all documents with that id, I just get the first document
const followingUsers = await User.find({ _id: { $in: foundUser.followings } })
const getFeedData = async() => {
for (let user of followingUsers) {
for (let postId of user.posts) {
console.log(postId)
}
}
}
I'm running this code when I console.log(postId) it returns all the posts with that id, but when I try to retrieve all documents with that id it returns just one document
findById will only return one record or null, an ID is the _id field on each document in a collection, which is a unique value
find is the equivalent of a where command in SQL, it returns as many documents that match the query, or an empty array
passing $in as a query to find looks for an array of matching document for the user id's
so if you already know the document _id's, then find will return the ID's so long you have passed an array of valid ObjectId
// (pretending these are real id's)
const arrayOfUserIds = [
ObjectId("5af619de653438ba9c91b291"),
ObjectId("5af619de653438ba9c91b293"),
ObjectId("5af619de653438ba9c91b297")
]
const users = await User.find({ _id: { $in: arrayOfUserIds } })
console.log(users.length)
users.forEach((user, index) => {
console.log(`${index} - `, user._id)
})
// => 3
// => 0 - ObjectId("5af619de653438ba9c91b291")
// => 1 - ObjectId("5af619de653438ba9c91b293")
// => 2 - ObjectId("5af619de653438ba9c91b297")