mongoose-counters

This plugin create fields which autoincrement their value every time a new document is inserted in a collection.

Installation

---

yarn add mongoose-counters
npm i mongoose-counters

Setup

---

This plugin accept a series of options.

• id: Id of the counter. Is mandatory only for scoped counters but its use is strongly encouraged.
• incField: The name of the field to increment. Mandatory, default is _id
• referenceFields: The field to reference for a scoped counter. Optional
• collectionName: The collection name to mantain the status of the counters. Mandatory, default is counters

Use as you would any Mongoose plugin:

import * as mongoose from 'mongoose';
import mongooseCounter from 'mongoose-counters';

const counter = mongooseCounter(mongoose);
const schema = new mongoose.Schema({ ... });
schema.plugin(counter, { ...options });
const model = model('MyModel', schema);

The increment can be:

• global: every document has a unique value for the counter field
• scoped: the counter depends on the value of other field(s)

Global counters

Let's say you want to have an id field in your collection which has an unique auto-incremented value.

The model schema is something like this:

ModelSchema = mongoose.Schema({
  myAttr: String
  ...
});

mongoose.model('ModelName', ModelSchema);

You don't need to define the id field in your schema because the plugin automatically set it for you. The only thing you have to do is to call:

ModelSchema.plugin(counter, { incField: 'id' });

Every time a new model entry is created, the id field will have an incremental number.

If you want to increment the _id field which is special to mongoose, you have to explicitly specify it as a Number and tell mongoose to not interfer:

ModelSchema = mongoose.Schema({
  _id: Number,
  myAttr: String
}, { _id: false });
ModelSchema.plugin(AutoIncrement);

In this case you don't have to specify incField because the default value is _id

Scoped counters

Let say our users are organized for country and city. And we want to save the inhabitant_number according to the two informations. The schema is like this:

UserSchema = mongoose.Schema({
    name: String,
    country: String,
    city: String,
    inhabitant_number: Number
});

Every time a new Parisian is added the counting of Parisians have to be incremented. The inhabitants of New York must not interfer and have their separated counting. We should define a scoped counter which increment the counter depending on the value of other fields.

UserSchema.plugin(AutoIncrement, {id: 'inhabitant_seq', inc_field: 'inhabitant_number', reference_fields: ['country','city'] });

Notice that we have to use an id for our sequence, otherwise the plugin will raise an error.

API

• resetCounter()

resetCounter()

It's possible to programmatically reset a counter through the Model static method counterReset(id, reference, callback). The method take those parameters:

• id: the counter to reset. It's mandatory
• reference: Let you reset only a specific reference of the counter, if the counter has referenced fields. Optional. By default it reset all the counters for the id
• callback: A callback which receive an error in case of any. Mandatory

Model.counterReset('the_counter_id', (err) => { ... });

Model.counterReset('the_counter_id', { ref_field_1: 'ref_value_1', ref_field_2: 'ref_value_2'}, (err) => { ... });

Credits

This plugin is inspired by ramiel/mongoose-sequence.