[mongodb] Mongoose's find method with $or condition does not work properly

Recently I start using MongoDB with Mongoose on Nodejs.

When I use Model.find method with $or condition and _id field, Mongoose does not work properly.

This does not work:

User.find({
  $or: [
    { '_id': param },
    { 'name': param },
    { 'nickname': param }
  ]
}, function(err, docs) {
   if(!err) res.send(docs);
});

By the way, if I remove the '_id' part, this DOES work!

User.find({
  $or: [
    { 'name': param },
    { 'nickname': param }
  ]
}, function(err, docs) {
   if(!err) res.send(docs);
});

And in MongoDB shell, both work properly.

According to mongoDB documentation: "...That is, for MongoDB to use indexes to evaluate an $or expression, all the clauses in the $or expression must be supported by indexes."

So add indexes for your other fields and it will work. I had a similar problem and this solved it.

You can read more here: https://docs.mongodb.com/manual/reference/operator/query/or/

I implore everyone to use Mongoose's query builder language and promises instead of callbacks:

User.find().or([{ name: param }, { nickname: param }])
    .then(users => { /*logic here*/ })
    .catch(error => { /*error logic here*/ })

Read more about Mongoose Queries.

async() => {
let body = await model.find().or([
  { name: 'something'},
  { nickname: 'somethang'}
]).exec();
console.log(body);
}
/* Gives an array of the searched query!
returns [] if not found */