$begins Mango Operator

[skeyby]

Summary

It would be cool to have a sugar-operator called $begins that is internally implemented as an AND of $gte a $lt to find any value starting with a desired pattern.

Desired Behaviour

The usage il something like this: let's suppose we want to find all people with surname starting with "Branca" either for autocompletition purpose or just because the user may have a second surname. Actually one could only do:

"Surname": {
 $eq: "Branca" 
}

That wouldn't find either "Brancatelli" nor "Branca SecondSurname"

The only solution would be to:

"Surname": { 
  $regex: "Branca"
}

That is unindexed.

Possible Solution

As in summary a solution could be to implement a sugar-operator called $begins that internally gets mapped to an AND-combination of $gte and $lt with an upper character as an upper bound. So, calling:

"Surname": {
 $begins: "Branca" 
}

would be translated in

$and: [
 { "Surname": { $gte: "Branca" } },
 { "Surname": { $lt: "Branca\ufff0" } }
]

That would use the index as expected.

[nickva]

This was implemented by @willholley in #4810!

Closing as completed.