为什么我的回叫功能无法运行？

Question

var user_col = db.collection('users');
var cursor = user_col.findOne({email:'testuser1@test.com', password:'test'}, function(err,doc){
            console.log("THIS IS A TEST");
    });

The problem with this code is the callback function does not seem to run. THIS IS A TEST does not get outputted.

I am connected to a database, db is passed into this function as an argument. What are the possible problems?

Answer 1

findOne() doesn't receive a callback as second parameter, the second one is a projection which means that if you define it will only return the specified parameters db.collection.findOne(query, projection) . That's way your callback is not been executed. findOne documentation here

Examples here

Updated:

According to the comments seems to be this docs (my mistake) , but the issue was the missing second parameter findOne(query, options, callback)