mongoose-auto-increment


> Mongoose plugin that auto-increments any ID field on your schema every time a document is saved.

---

> This is the module used by mongoose-simpledb to increment Number IDs. You are perfectly able to use this module by itself if you would like. However, if you're looking to make your life easier when using mongoose then I highly recommend you check out simpledb. It's a small wrapper around mongoose but it makes it extremely easy to deal with your models and draws a clear path for how to use mongoose in your application.

Getting Started

> npm install mongoose-auto-increment

Once you have the plugin installed it is very simple to use. Just get reference to it, initialize it by passing in your
mongoose connection and pass autoIncrement.plugin to the plugin() function on your schema.

> Note: You only need to initialize MAI once.

```js
var mongoose = require('mongoose'),
Schema = mongoose.Schema,
autoIncrement = require('mongoose-auto-increment');

var connection = mongoose.createConnection("mongodb://localhost/myDatabase");

autoIncrement.initialize(connection);

var bookSchema = new Schema({
author: { type: Schema.Types.ObjectId, ref: 'Author' },
title: String,
genre: String,
publishDate: Date
});

bookSchema.plugin(autoIncrement.plugin, 'Book');
var Book = connection.model('Book', bookSchema);
``

That's it. Now you can create book entities at will and they will have an _id field added of type Number and will automatically increment with each new document. Even declaring references is easy, just remember to change the reference property's type to Number instead of ObjectId if the referenced model is also using the plugin.

``js
var authorSchema = new mongoose.Schema({
name: String
});

var bookSchema = new Schema({
author: { type: Number, ref: 'Author' },
title: String,
genre: String,
publishDate: Date
});

bookSchema.plugin(autoIncrement.plugin, 'Book');
authorSchema.plugin(autoIncrement.plugin, 'Author');
``

$3

``js
bookSchema.plugin(autoIncrement.plugin, { model: 'Book', field: 'bookId' });
``

$3

``js
bookSchema.plugin(autoIncrement.plugin, {
model: 'Book',
field: 'bookId',
startAt: 100,
incrementBy: 100
});
``

Your first book document would have a bookId equal to 100. Your second book document would have a bookId equal to 200, and so on.

$3

``js
var Book = connection.model('Book', bookSchema);
Book.nextCount(function(err, count) {

// count === 0 -> true

var book = new Book();
book.save(function(err) {

// book._id === 0 -> true

book.nextCount(function(err, count) {

// count === 1 -> true

});
});
});
``

nextCount is both a static method on the model (Book.nextCount(...)) and an instance method on the document (book.nextCount(...)).

$3

``js
bookSchema.plugin(autoIncrement.plugin, {
model: 'Book',
field: 'bookId',
startAt: 100
});

var Book = connection.model('Book', bookSchema),
book = new Book();

book.save(function (err) {

// book._id === 100 -> true

book.nextCount(function(err, count) {

// count === 101 -> true

book.resetCount(function(err, nextCount) {

// nextCount === 100 -> true

});

});

});
```