README

baldercm/mongoose-bignumber

Mongoose type for storing arbitrary-precision decimal numbers (using bignumber.js).

Use the power of BigNumber instances in your model and obtain seamlessly conversion to String values when saving to MongoDB and serializing as JSON.

Installation

Install the module using npm:

npm i mongoose-bignumber

mongoose and bignumber.js are declared as peerDependencies, so you have to install these dependencies yourself if you are not using them yet:

npm i mongoose bignumber.js mongoose-bignumber

Basic Usage

Require the module and use it in your schema:

const mongoose        = require('mongoose')
const BigNumber       = require('bignumber.js')
const BigNumberSchema = require('mongoose-bignumber')

// you may use BigNumberSchema or mongoose.Schema.Types.BigNumber
// standard number validators work for Number, String and BigNumber values
const exampleSchema = new mongoose.Schema({
  val1:  { type: BigNumberSchema, required: true, min: '0' },
  val2:  { type: BigNumberSchema, scale: 2, rounding: BigNumber.ROUND_HALF_UP },
  val2:  { type: BigNumberSchema, scale: 2, max: new BigNumber('99.99') },
  val3:  { type: mongoose.Schema.Types.BigNumber },
})

const Example = mongoose.model('Example', exampleSchema)

The only overwritten method for BigNumberSchema that will differ from a regular BigNumber is valueOf(), that will behave like toFixed() using the specified scale and rounding options.

Options

Supports required, min, max validators.

scale and rounding schema options will be applied when saving to MongoDB or serializing with toJSON or toObject.

`scale {int}`

Sets the scale (decimal precision).

scale defaults to 0.

`rounding {int}`

Sets the BigNumber rounding method. See bignumber.js docs for more details.

rounding defaults to BigNumber.ROUND_HALF_UP.

Example

const mongoose        = require('mongoose')
const BigNumber       = require('bignumber.js')
const BigNumberSchema = require('mongoose-bignumber')

const exampleSchema = new mongoose.Schema({
  bignumber: { type: BigNumberSchema, scale: 2, rounding: BigNumber.ROUND_HALF_UP },
  // will format using:    BigNumber.toFixed(2, BigNumber.ROUND_HALF_UP)
})

const Model = mongoose.model('Example', exampleSchema)

let model = new Model({bignumber: '23.456789'})
await model.save() // {_id: ..., bignumber: '23.46'}

// model.bignumber is a BigNumber instance
assert(model.bignumber instanceof BigNumber)

// and we can use it as a regular BigNumber
// {_id: ..., bignumber: '23.46'}
model.bignumber = model.bignumber.add('11.11')
// {_id: ..., bignumber: '34.57'}

// BigNumber instances are immutable, this won't change the model!
// {_id: ..., bignumber: '34.57'}
model.bignumber.add('11.11')
// {_id: ..., bignumber: '34.57'}

Contributing

git clone https://github.com/baldercm/mongoose-bignumber
npm install
npm test
npm run lint

License

MIT

Usage no npm install needed!