how to make queries find in mongoose with condition where value a == b?

Question

how to make queries find in mongoose with condition where value user == to ?

this is the json data:

{
    "_id": {
        "$oid": "5ad8096151fe2d391cae9110"
    },
    "user": {
        "$oid": "5acc15622ec84a0bb4200fdb"
    },
    "to": {
        "$oid": "5acc16e92ec84a0bb4200fdc"
    },
    "message": "hello",
    "status": "pending",
    "created": {
        "$date": "2018-04-19T03:13:37.257Z"
    },
    "__v": 0
}