MongoDB created collection shows in NodeJS but not in CLI? - node.js

Question

I am trying to create a capped collection in MongoDB using NodeJS driver.
db.createCollection(req.body.name,options,function onCreateCollection(mongoErr,mongoCollection){
if(mongoErr){
...
}else{
console.log( mongoCollection.collectionName );
...
}
});
The collection name prints on the console but show collections does not list it. I tried a hyphenated name this-is-a-collection.
Why is that?
Also, what are the limitations in naming a collection?

Answer 1

I don't know why your code doesn't work. But I just tried to create a collection with the hyphenated name this-is-a-collection with this simple script, it worked.
var MongoClient = require('mongodb').MongoClient;
var url = 'mongodb://localhost:27017/db';
MongoClient.connect(url, function(err, db) {
console.log("Connected correctly to server");
db.createCollection('this-is-a-collection', { capped : true, size : 10000 } ,function onCreateCollection(err,mongoCollection){
if(err){
console.log(err);
} else {
console.log(mongoCollection.collectionName);
}
db.close();
});
});
And in the CLI :
MBP:mongo sapher$ mongo
MongoDB shell version: 3.0.5
connecting to: test
....
> use db
switched to db db
> show collections
system.indexes
this-is-a-collection
You can follow this link to get more info on MongoDB naming restrictions.
For naming convention, I personnaly use snake case like remote_users. I think this is the most elegant way to name a collection. Naming isn't that important as long as you stay consistent.

Answer 2

As it turns out, on older version of the driver 1.4.x, creating a capped collection without specifying the size option doesn't result in an error. It even returns a success response. On the newer version, 2.0.x, it does result in an error.
For a capped collection, size is needed while max is optional. The docs are slightly ambiguous as they do not state that you need a size to create a capped collection.