[node.js] How to drop a database with Mongoose?

I'm preparing a database creation script in Node.js and Mongoose. How can I check if the database already exists, and if so, drop (delete) it using Mongoose?

I could not find a way to drop it with Mongoose.

Since the remove method is depreciated in the mongoose library we can use the deleteMany function with no parameters passed.

Model.deleteMany();

This will delete all content of this particular Model and your collection will be empty.

If you modify @hellslam's solution like this then it will work

I use this technique to drop the Database after my integration tests

//CoffeeScript
mongoose = require "mongoose"
conn = mongoose.connect("mongodb://localhost/mydb")

conn.connection.db.dropDatabase()

//JavaScript
var conn, mongoose;
mongoose = require("mongoose");
conn = mongoose.connect("mongodb://localhost/mydb");

conn.connection.db.dropDatabase();

HTH at least it did for me, so I decided to share =)

mongoose.connect(`mongodb://localhost/${dbname}`, {
        useNewUrlParser: true,
        useCreateIndex: true,
        useFindAndModify: true,
        useUnifiedTopology: true
    })
        .then((connection) => {
            mongoose.connection.db.dropDatabase();
        });

To delete a complete database, just pass the name... This one is working perfectly fine on version 4.4

beforeEach((done) => {
      mongoose.connection.dropCollection('products',(error ,result) => {
      if (error) {
        console.log('Products Collection is not dropped')
      } else {
        console.log(result)
      }
    done()
    })
  })

An updated answer, for 4.6.0+, if you have a preference for promises (see docs):

mongoose.connect('mongodb://localhost/mydb', { useMongoClient: true })
.then((connection) => {
   connection.db.dropDatabase();
   // alternatively:
   // mongoose.connection.db.dropDatabase();
});

I tested this code in my own code, using mongoose 4.13.6. Also, note the use of the useMongoClient option (see docs). Docs indicate:

Mongoose's default connection logic is deprecated as of 4.11.0. Please opt in to the new connection logic using the useMongoClient option, but make sure you test your connections first if you're upgrading an existing codebase!

For dropping all documents in a collection:

myMongooseModel.collection.drop();

as seen in the tests

Mongoose will create a database if one does not already exist on connection, so once you make the connection, you can just query it to see if there is anything in it.

You can drop any database you are connected to:

var mongoose = require('mongoose');
/* Connect to the DB */
mongoose.connect('mongodb://localhost/mydatabase',function(){
    /* Drop the DB */
    mongoose.connection.db.dropDatabase();
});

To drop all documents in a collection:

await mongoose.connection.db.dropDatabase();

This answer is based off the mongoose index.d.ts file:

dropDatabase(): Promise<any>;

The best way to drop your database in Mongoose depends on which version of Mongoose you are using. If you are using a version of Mongoose that 4.6.4 or newer, then this method added in that release is likely going to work fine for you:

mongoose.connection.dropDatabase();

In older releases this method did not exist. Instead, you were to use a direct MongoDB call:

mongoose.connection.db.dropDatabase();

However, if this was run just after the database connection was created, it could possibly fail silently. This is related to the connection actually be asynchronous and not being set up yet when the command happens. This is not normally a problem for other Mongoose calls like .find(), which queue until the connection is open and then run.

If you look at the source code for the dropDatabase() shortcut that was added, you can see it was designed to solve this exact problem. It checks to see if the connection is open and ready. If so, it fires the command immediately. If not, it registers the command to run when the database connection has opened.

Some of the suggestions above recommend always putting your dropDatabase command in the open handler. But that only works in the case when the connection is not open yet.

Connection.prototype.dropDatabase = function(callback) {
  var Promise = PromiseProvider.get();
  var _this = this;
  var promise = new Promise.ES6(function(resolve, reject) {
    if (_this.readyState !== STATES.connected) {
      _this.on('open', function() {
        _this.db.dropDatabase(function(error) {
          if (error) {
            reject(error);
          } else {
            resolve();
          }
        });
      });
    } else {
      _this.db.dropDatabase(function(error) {
        if (error) {
          reject(error);
        } else {
          resolve();
        }
      });
    }
  });
  if (callback) {
    promise.then(function() { callback(); }, callback);
  }
  return promise;
};

Here's a simple version of the above logic that can be used with earlier Mongoose versions:

// This shim is backported from Mongoose 4.6.4 to reliably drop a database
// http://stackoverflow.com/a/42860208/254318
// The first arg should be "mongoose.connection"
function dropDatabase (connection, callback) {
    // readyState 1 === 'connected'
    if (connection.readyState !== 1) {
      connection.on('open', function() {
        connection.db.dropDatabase(callback);
      });
    } else {
      connection.db.dropDatabase(callback);
    }
}  

Mongoose 4.6.0+:

mongoose.connect('mongodb://localhost/mydb')
mongoose.connection.once('connected', () => {
    mongoose.connection.db.dropDatabase();
});

Passing a callback to connect won't work anymore:

TypeError: Cannot read property 'commandsTakeWriteConcern' of null

To empty a particular collection in a database:

model.remove(function(err, p){
    if(err){ 
        throw err;
    } else{
        console.log('No Of Documents deleted:' + p);
    }
});

Note:

1. Choose a model referring to particular schema(schema of collection you wish to delete).
2. This operation will not delete collection name from database.
3. This deletes all the documents in a collection.

2020 update

make a new file call it drop.js i.e and put inside

require('dotenv').config()
const url = process.env.ATLAS_URI;
mongoose.connect(url, {
  useNewUrlParser: true,
  useCreateIndex: true,
  useUnifiedTopology: true,
  useFindAndModify: false
});

const connection = mongoose.connection;
connection.once('open', () => {
  console.log("MongoDB database connection established successfully");
})


mongoose.connection.dropDatabase().then(
  async() => {
   
    try {
      mongoose.connection.close()
     
    }
    catch (err) {
      console.log(err)
    }

 }
  
);

in your package.json

in your package.json 
 "scripts": {
    
    "drop": "node models/drop.js",
   
  }

run it on ur console and

Tried @hellslam's and @silverfighter's answers. I found a race condition holding my tests back. In my case I'm running mocha tests and in the before function of the test I want to erase the entire DB. Here's what works for me.

var con = mongoose.connect('mongodb://localhost/mydatabase');
mongoose.connection.on('open', function(){
    con.connection.db.dropDatabase(function(err, result){
        done();
    });
});

You can read more https://github.com/Automattic/mongoose/issues/1469

The difficulty I've had with the other solutions is they rely on restarting your application if you want to get the indexes working again.

For my needs (i.e. being able to run a unit test the nukes all collections, then recreates them along with their indexes), I ended up implementing this solution:

This relies on the underscore.js and async.js libraries to assemble the indexes in parellel, it could be unwound if you're against that library but I leave that as an exerciser for the developer.

mongoose.connection.db.executeDbCommand( {dropDatabase:1}, function(err, result) {
  var mongoPath = mongoose.connections[0].host + ':' + mongoose.connections[0].port + '/' + mongoose.connections[0].name
  //Kill the current connection, then re-establish it
  mongoose.connection.close()
  mongoose.connect('mongodb://' + mongoPath, function(err){
    var asyncFunctions = []

    //Loop through all the known schemas, and execute an ensureIndex to make sure we're clean
    _.each(mongoose.connections[0].base.modelSchemas, function(schema, key) {
      asyncFunctions.push(function(cb){
        mongoose.model(key, schema).ensureIndexes(function(){
          return cb()
        })
      })
    })

    async.parallel(asyncFunctions, function(err) {
      console.log('Done dumping all collections and recreating indexes')
    })
  })
})

This works for me as of Mongoose v4.7.0:

mongoose.connection.dropDatabase();