mongojs/README.md

# mongojs

A [node.js](http://nodejs.org) module for mongodb, that emulates [the official mongodb API](http://www.mongodb.org/display/DOCS/Home) as much as possible.
It wraps [mongodb-native](https://github.com/mongodb/node-mongodb-native/) and is available through [npm](http://npmjs.org)

	npm install mongojs

[![build status](https://secure.travis-ci.org/mafintosh/mongojs.png)](http://travis-ci.org/mafintosh/mongojs)

## Usage

mongojs is easy to use:

``` js
var mongojs = require('mongojs');
var db = mongojs(connectionString, [collections]);
```

The connection string should follow the format desribed in [the mongo connection string docs](http://docs.mongodb.org/manual/reference/connection-string/).
Some examples of this could be:

``` js
// simple usage for a local db
var db = mongojs('mydb', ['mycollection']);

// the db is on a remote server (the port default to mongo)
var db = mongojs('example.com/mydb', ['mycollection']);

// we can also provide some credentials
var db = mongojs('username:password@example.com/mydb', ['mycollection']);

// connect now, and worry about collections later
var db = mongojs('mydb');
var mycollection = db.collection('mycollection');
```

After we connected we can query or update the database just how we would using the mongo API with the exception that we use a callback.
The format for callbacks is always `callback(error, value)` where error is null if no exception has occured. The update methods `save`, `remove`, `update` and `findAndModify` also pass the `lastErrorObject` as the last argument to the callback function.

``` js
// find everything
db.mycollection.find(function(err, docs) {
	// docs is an array of all the documents in mycollection
});

// find everything, but sort by name
db.mycollection.find().sort({name:1}, function(err, docs) {
	// docs is now a sorted array
});

// iterate over all whose level is greater than 90.
db.mycollection.find({level:{$gt:90}}).forEach(function(err, doc) {
	if (!doc) {
		// we visited all docs in the collection
		return;
	}
	// doc is a document in the collection
});

// find a document using a native ObjectId
db.mycollection.findOne({
	_id:mongojs.ObjectId('523209c4561c640000000001')
}, function(err, doc) {
	// doc._id.toString() === '523209c4561c640000000001'
});

// find all named 'mathias' and increment their level
db.mycollection.update({name:'mathias'}, {$inc:{level:1}}, {multi:true}, function() {
	// the update is complete
});

// find one named 'mathias', tag him as a contributor and return the modified doc
db.mycollection.findAndModify({
	query: { name: 'mathias' },
	update: { $set: { tag:'maintainer' } },
	new: true
}, function(err, doc, lastErrorObject) {
	// doc.tag === 'maintainer'
});


// use the save function to just save a document (callback is optional for all writes)
db.mycollection.save({created:'just now'});

```

If you provide a callback to `find` or any cursor config operation mongojs will call `toArray` for you

``` js
db.mycollection.find({}, function(err, docs) { ... });

db.mycollection.find({}).limit(2).skip(1, function(err, docs) { ... });
```
is the same as

``` js
db.mycollection.find({}).toArray(function(err, docs) { ... });

db.mycollection.find({}).limit(2).skip(1).toArray(function(err, docs) { ... });
```

For more detailed information about the different usages of update and quering see [the mongo docs](http://www.mongodb.org/display/DOCS/Manual)

## Streaming cursors

As of `0.7.0` all cursors are a [readable stream](http://nodejs.org/api/stream.html#stream_readable_stream) of objects.

``` js
var JSONStream = require('JSONStream');

// pipe all documents in mycollection to stdout
db.mycollection.find({}).pipe(JSONStream.stringify()).pipe(process.stdout);
```

Notice that you should pipe the cursor through a stringifier (like [JSONStream](https://github.com/dominictarr/JSONStream))
if you want to pipe it to a serial stream like a http response.

## Tailable cursors

If you are using a capped collection you can create a [tailable cursor](http://docs.mongodb.org/manual/tutorial/create-tailable-cursor/) to that collection by adding `tailable:true` to the find options

``` js
var cursor = db.mycollection.find({}, {}, {tailable:true, timeout:false});

// since all cursors are streams we can just listen for data
cursor.on('data', function(doc) {
	console.log('new document', doc);
});
```

Note that you need to explicitly set the selection parameter in the `find` call.

## Database commands

With mongojs you can run database commands just like with the mongo shell using `db.runCommand()`

```js
db.runCommand({ping:1}, function(err, res) {
	if(!err && res.ok) console.log("we're up");
});
```

or `db.collection.runCommand()`

```js
db.things.runCommand('count', function(err, res) {
	console.log(res);
});
```

## Replication Sets

Mongojs can also connect to a mongo replication set by providing a connection string with multiple hosts

``` js
var db = mongojs('rs-1.com,rs-2.com,rs-3.com/mydb?slaveOk=true', ['mycollection']);
```

For more detailed information about replica sets see [the mongo replication docs](http://www.mongodb.org/display/DOCS/Replica+Sets)

## Using with harmony

If you run node.js with the `--harmony` option, then you can ommit the collection names array, and you can do stuff like.

```js
var mongojs = require('mongojs');
var db = require('mydb');

db.hackers.insert({name: 'Ed'});
```

# API

This API documentation is a work in progress.

#### Collection

#####`db.collection.aggregate([pipeline], [callback])`

#####`db.collection.count([query], callback)`

#####`db.collection.createIndex(keys, options, [callback])`

#####`db.collection.distinct(field, query, callback)`

#####`db.collection.drop([callback])`

#####`db.collection.dropIndex(index, [callback])`

#####`db.collection.dropIndexes([callback])`

#####`db.collection.ensureIndex(keys, options, [callback])`

#####`db.collection.find([criteria], [projection], [callback])`

This function applies a query to a collection. You can get the return value, which is a cursor, or pass a callback
as the last parameter. Said callback receives `(err, documents)`

#####`db.collection.findOne([criteria], [projection], callback)`

Apply a query and get one single document passed as a callback. The callback receives `(err, document)`

#####`db.collection.findAndModify(document, callback)`

#####`db.collection.getIndexes(callback)`

#####`db.collection.group(document, callback)`

#####`db.collection.insert(docOrDocs, [callback])`

#####`db.collection.isCapped(callback)`

#####`db.collection.mapReduce(map, reduce, options, [callback])`

#####`db.collection.reIndex([callback])`

#####`db.collection.remove(query, [justOne], [callback])`

#####`db.collection.runCommand(command, [callback])`

#####`db.collection.save(doc, [callback])`

#####`db.collection.stats(callback)`

#####`db.collection.update(query, update, [options], [callback])`

#### Cursor

#####`cursor.batchSize(size, [callback])`

#####`cursor.count(callback)`

#####`cursor.explain(callback)`

#####`cursor.forEach(function)`

#####`cursor.limit(n, [callback])`

#####`cursor.map(function, [callback])`

#####`cursor.next(callback)`

#####`cursor.skip(n, [callback])`

#####`cursor.sort(sortOptions, [callback])`

#####`cursor.toArray(callback)`

#### Database

#####`db.addUser(document)`

#####`db.createCollection(name, options, [callback])`

#####`db.dropDatabase([callback])`

#####`db.eval(code, [params], [options], [callback])`

#####`db.getCollectionNames([callback])`

#####`db.getLastError(callback)`

#####`db.getLastErrorObj(callback)`

#####`db.removeUser(username, [callback])`

#####`db.runCommand(command, [callback])`

#####`db.stats([callback])`