Call function inside mongodb's aggregate?

Question

Collection:

[
    { _id: \"Foo\", flag1: false, flag2: true, flag3: false },
    { _id: \"Bar\", flag1: true, flag2: false, flag3: true }
]

Answer 1

Yes we can call function in aggregation project with simple way.

let getStatus = (flag) => {
    return flag=='ok' ? 'ok' :'broken';
}
aggregate({
    $project: {
        '_id': 1,
        'status': getStatus($flag3)
    }
});