How to drop all collections via mongodb and node.js? - node.js

Question

I am new to node.js and mongodb and I have the following problem:
I need to drop all collections from my mongodb from node.js file. I have such a function:
service.dropCollections = function(db, colls){
for(var i = 0; i < colls.length; i++){
var name = colls[i].name;
db.dropCollection(name, function(err) {
if(!err) {
console.log( name + " dropped");
} else {
console.log("!ERROR! " + err.errmsg);
}
});
}
}
And I am using it in the following function:
service.clearDB = function() {
var MongoClient = require('mongodb').MongoClient
, format = require('util').format;
MongoClient.connect('mongodb://127.0.0.1:27017/shiny_d', function(err, db){
if(err) throw err;
db.collectionNames(function(err, collections){
if(!err){
service.dropCollections(db, collections);
} else {
console.log("!ERROR! "+ err.errmsg);
}
service.showCollections();
});
});
}
As an output I have
!ERROR! ns not found
shiny_db.physicalinfos
Dunno what to do right now. I'll be very thankful for your help.

Answer 1

Ain't it more faster, easier and less error prone if you just drop the entire database?
db.dropDatabase();
At least from the Mongo CLI, whenever you access an inexistent DB, it'll be persisted the soon you create data. That's the same as dropping all collections from it.
I haven't tried MongoDB for anything except studying yet, so I don't know much about permissions. So, probably the only problem of dropping the entire DB would be the permissions of your users that would be lost (I believe).
If this script you're trying to create is not for production, then you're good to go with dropping the DB.

Answer 2

I found an answer. First of all I've made mistake in my connection it should be like following: 'mongodb://127.0.0.1:27017/shiny_db'. The second mistake was in the name of collection. It was like 'db_name.coll_name', that's why db.dropCollection(name, callback) couldn't find particular collection and because of it I had mistake ns not found. So I've used following mechanism to separate db_name from coll_name:
var name = colls[i].name.substring('shiny_db.'.length); and I've added checking for "system" collection.
Final code looks like following:
service.clearDB = function() {
var MongoClient = require('mongodb').MongoClient
, format = require('util').format;
MongoClient.connect('mongodb://localhost/shiny_db', function(err, db) {
if(err) throw err;
db.collectionNames(function(err, collections){
if(!err){
service.dropCollections(db, collections);
} else {
console.log("!ERROR! "+ err.errmsg);
}
});
});
}
service.dropCollections = function(db, colls){
for(var i = 0; i < colls.length; i++){
var name = colls[i].name.substring('shiny_db.'.length);
if (name.substring(0, 6) !== "system") {
db.dropCollection(name, function(err) {
if(!err) {
console.log( name + " dropped");
} else {
console.log("!ERROR! " + err.errmsg);
}
});
} else {
console.log(name + " cannot be dropped because it's a system file");
}
}
}
Hope it will help someone!

Answer 3

listCollections gives you an array of collection names as strings.
It looks like you may be confusing it with something that returns an array of collection objects like maybe db.collections()