how do I do "show collections" in mongojs code?

[xiaochunmei]

Mongo db shell support "show collections" to list all the collections of a database.
How do I do this in javascript using mongojs?

[sorribas]

While show collections itself is a mongo shell command and is not really JavaScript, you can get the list of collections with mongojs with something like the following:

var mongojs = require('mongojs');
var db = mongojs('test', []);

db.collections(function(e, cols) {
    cols.forEach(function(col) {
        console.log(col.collectionName);
    });
});

I hope this helps :)

[repoman]

There is something called getCollectionNames() in the docs. Would be nice to see it in mongojs as well, not a big deal though.

[mafintosh]

db.getCollectionNames() has been added in 0.7.12 (see #73)

[xiaochunmei]

Thanks all.

[mb21]

Am I missing something or is this currently (mongojs 0.13.1) broken?

> var mongojs = require("mongojs");
> var db = mongojs.connect("apis", ["apis"]);
> db.getCollectionNames
[Function]
> db.getCollectionNames()
undefined
> 
~/code/node_modules/mongojs/node_modules/mongodb/lib/mongodb/connection/base.js:245
        throw message;      
              ^
TypeError: undefined is not a function
    at ~/code/node_modules/mongojs/index.js:408:4
    at ~/code/node_modules/mongojs/node_modules/mongodb/lib/mongodb/db.js:524:5
    at ~/code/node_modules/mongojs/node_modules/mongodb/lib/mongodb/db.js:445:7
    at ~/code/node_modules/mongojs/node_modules/mongodb/lib/mongodb/cursor.js:163:16
    at commandHandler (~/code/node_modules/mongojs/node_modules/mongodb/lib/mongodb/cursor.js:706:16)
    at ~/code/node_modules/mongojs/node_modules/mongodb/lib/mongodb/db.js:1843:9
    at Server.Base._callHandler (~/code/node_modules/mongojs/node_modules/mongodb/lib/mongodb/connection/base.js:445:41)
    at ~/code/node_modules/mongojs/node_modules/mongodb/lib/mongodb/connection/server.js:468:18

[sorribas]

@mb21 You have to pass a callback to the getCollectionNames function. So you should do something like this.

db.getCollectionNames(function(err, colNames) {
  if (err) return  console.log(err);
  colNames.forEach(function(name) {
    console.log(name);
  });
});

[mb21]

@sorribas Thanks, that worked!

In the README, the callback then should not be optional: db.getCollectionNames(callback) instead of db.getCollectionNames([callback]).

[sorribas]

@mb21 Good point. Will fix.

[AndrewKralovec]

db.getCollectionNames(function(err, colNames) {
if (err) return console.log(err);
colNames.forEach(function(name) {
console.log(name);
});
});

This will just list the collections, which is already using inside the mongojs call // var db = mongojs(connectionString, [collections]
So pointless.
You will have to use mongodb and then use the admin option

// Use the admin database for the operation
var adminDb = db.admin();

// List all the available databases
adminDb.listDatabases(function(err, dbs) {
assert.equal(null, err);
assert.ok(dbs.databases.length > 0);
console.log(dbs);
db.close();
});
});