MongoDB Queries

Find duplicates in an Array - embedded object.js

m = function () {
    if(this.Model === 1) { // business logic specific, to remove if not need (allows to filter un-wanted values / keys)
        for(var i in this.embed) {
            key = i;   // the key to look dupes for
            value = 1; // cnt
            emit(key, value);
        }
    }
}

r = function (key, values) {
    return Array.sum(values);
}
db.MediaPlan.mapReduce(m, r,  {out: {inline: 1}})

Find duplicates in Mongo.js

m = function () {
    emit(this.ID, 1);
}

r = function (k, vals) {
    return Array.sum(vals);
}
db.Vehicle.mapReduce(m, r,  {out: {inline: 1}, query: {value: {$gt: 1}}})