MapReduce of MongoDB puts the result in `values` field. Sometimes one wants the result to be a document and not a pair `(_id, values)`. The function below flattens the result of map_reduce.

flatten_map_reduce

function(table) {
    db[table].find().forEach(function(x) {
        var update = { $set: {}, $unset: { value: '' } }
        for (var k in x.value)
            update.$set[k] = x.value[k]
        db[table].update({_id: x._id}, update)
    })
}