MongoDB : How to find by the sublevels ?

You have a BSON with an array of objects and you want to find by the objects inside so it’s really easy.

Use the ( ‘ ) to make the field definition

Example:

return Events.find({'sessions.dt_start': { $exists: true },'sessions.dt_start':{$gte:dtStart,$lte:dtEnd}},{sort:{createdAt: -1}});