How to compose a mongodb query with an empty array?

Question

MongoDB

Actually I try to make request on two fields. One of the fields receives an empty array. Finds nothing. How to do what would find? Or make this field optional?

var shops = [123, 345, 567];
var types = [];

{
      'shops': {
        $in: shops
      },
      'types':  {
        $in: types
      }
}

Answer 1

Build the query dynamically

var shops = [123, 345, 567];
var types = [];

var query = {};
if(shops.length) {
  query.shops = { $in: shops };
}
if(types.length) {
  query.types = { $in: types };
}

Answer 2

If there is an initial array of all types, I would assign this value to var types if the type array that came from the source was empty, like this:

var types = types_from_source ? types_from_source : all_types