How to get update confirmation in mongodb nodejs driver?

Question

I am using the mpmodb npm module to connect to my mongo database using nodejs.

My simple example: I need to update a document in a collection that may or may not exist.

So, if the document exists, I should be able to update it and send a confirmation in my api response.

If the document does not exist, I must respond with a corresponding message that the document does not exist.

In principle, a very simple use case.

Here is how I update:

var MongoClient = require('mongodb').MongoClient;

MongoClient.connect(url, function(conn_err, db) {
    if (conn_err) {
        console.log("Error connecting to mongodb server!!");
        console.error(conn_err);
    } else {
        console.log("Connected to mongodb server!!");
        var collection = db.collection("test");

        collection.updateOne(query, {"$set": data}, {w: "majority"}, function (err, result) {
            console.error(err);
            console.log(result);
        });
    }
});

Now in resultthe callback I get an object containing a lot of things, but mainly:

result: { ok: 1, nModified: 1, n: 1 }
...
matchedCount: 1,
modifiedCount: 1,   
upsertedId: null,
upsertedCount: 0 

Now this is where my problem begins.

1) If the document exists and is updated, I get:

result: { ok: 1, nModified: 1, n: 1 },
...
matchedCount: 1,
modifiedCount: 1,   
upsertedId: null,
upsertedCount: 0

2) , ( $set , db), :

result: { ok: 1, nModified: 0, n: 1 },
...
matchedCount: 1,
modifiedCount: 0,   
upsertedId: null,
upsertedCount: 0

3) , :

result: { ok: 1, nModified: 0, n: 1 },
...
matchedCount: 1,
modifiedCount: 0,   
upsertedId: null,
upsertedCount: 0

, 2) 3)? .

- ?

: mongodb v3.0.7, nodejs v4.2.2, mongodb npm module v2.0.x

Answer 1

$set https://docs.mongodb.org/v3.0/reference/operator/update/set/ , , . , , . , , .

/

, , . . MongoDB , $, $gt or $lt or $nor (, , " , " ), . https://docs.mongodb.org/v3.0/reference/operator/query/nor/

. , , , , () , , , , , , .

collection.updateOne(query, {"$set": data},{w: "majority"},function (err,result){ console.error(err);console.log(result); });