Console log in MongoDB Shell

Question

I want to write functions into MongoDB Shell like this:

var last = function(collection) { db[collection].find().sort({_id: -1}).limit(1).toArray(); }

But there is one problem. When I call last() function, it will make no output. How to fix it?

Answer 1

You need to use either use the JavaScript print() function or the mongo specific printjson() function which returns formatted JSON to actually log to output the result from the find method, for example:

var last = function(collection) { 
    var doc = db.getCollection(collection).find().sort({_id: -1}).limit(1).toArray(); 
    printjson(doc); 
};
last("test");