猫鼬findOne数组的ObjectId返回null

Question

Having some issues performing a findOne query with an array of ObjectIds. Simplified schema as follows:

Model:

var InboxSchema = new Schema({
    _users: [
        {
            type: mongoose.Schema.ObjectId,
            ref: 'User',
            required: 'Users are required',
            unique: true
        }
    ]
}

mongoose.model('Inbox', InboxSchema)

Query:

var users = [];
var userIds = ['5567ead844997f969fe3f00f', '558b8492f1723b090b414765'];

for (var i=0; i<userIds.length; i++) {
    users.push(new mongoose.Types.ObjectId(userIds[i]));
}

Inbox.findOne({_users: users}).exec(function (err, inbox) {
    console.log(inbox);
}

Inbox always returns null despite it returning something when using Mongo shell, so I know that my query works. Previously, I was querying on just userIds alone, which I later realised was not working as I would have to query using ObjectId. However, even converting the strings to ObjectId doesn't work.

Answer 1

Try using the mongo array query operators $all or $in .

$all to match a target to all of the array elements:

Inbox.findOne({ "_users": { "$all": users} }).exec(function (err, inbox) {
    console.log(inbox);
})

$in to match a target to any of the array elements:

Inbox.findOne({ "users": { "$in": users} }).exec(function (err, inbox) {
    console.log(inbox);
})