remove a field from mongodb query result in golang

Question

This is my function from mongodb-go-driver:

func MongodbFindOne(key, value string) bson.M {
    var result bson.M
    opts := options.FindOne().SetShowRecordID(false)
    _ = Collection.FindOne(context.TODO(), bson.M{key: value}, opts).Decode(&result)
    return result
}

The function works very good but i get _id field in the result. I know the mongodb query to exclude a field from query result, But i don't know how to use it with FindOne() function:

From tutorialspoint:

db.removeIdDemo.find({},{_id:0});

From mongodb query result without field name

db.collection.find({},{_id:0, t_number:1}).toArray().map(function(ele) {return ele.t_number} );

From remove _id from mongo result (nodejs):

app.get('/itesms', function(req, res) {   items.find({}, { _id: 0 }).toArray(function (err, array) {
    res.send(array);   }) });

Answer 1

To exclude fields from the result, use a projection. Use FindOneOptions.SetProjection() to set the projection.

To specifically exclude the _id field:

err = c.FindOne(ctx,
    bson.M{key: value},
    options.FindOne().SetProjection(bson.M{"_id": 0}),
).Decode(&result)