Mongoose find array with $in

问题:

Team.find({
        '_id': { $in: [
            teamIds
        ] }
    }, function(err, teamData) {
        console.log("teams name  " + teamData);
    });

This code gives us undefined back.. But in the var teamIds is this:

545646d5f5c1cce828982eb7,
545646d5f5c1cce828982eb8,
54564af5c9ddf61e2b56ad1e,
54564c1f1de201782bcdb623,
54564d2fc660a7e12be6c7a2,
54564df985495f142c638f9f,
54564eadb511f1792c9be138,
54564ec40cf6708a2cd01c81,
54564ee495f4aea22cf23728

Does anybody see the error?

回答1:

If teamIds is already an array, then you shouldn't wrap it in another array:

Team.find({
    '_id': { $in: teamIds }
}, function(err, teamData) {
    console.log("teams name  " + teamData);
});

Or, if teamIds is a string of comma-separated id values, you need to convert it into an array of values using split:

Team.find({
    '_id': { $in: teamIds.split(',') }
}, function(err, teamData) {
    console.log("teams name  " + teamData);
});