mongodb subdocument array match and or code example

Example 1: how to get array object value in mongodb

db.products.aggregate([
    {$unwind: "$ratings"},
    {$match: {'ratings.user': ObjectId("5f6e2e0b70eb0208fc8401a1")}}
])

Example 2: mongodb find array with element

// Finds all documents that have a property named "tags"
// which has at least one array element matching "red"
db.inventory.find( { tags: "red" } )