How should i store a price in mongoose?

In Mongoose, storing price data typically involves selecting the appropriate data type to ensure data accuracy and proper handling. For price data, the most common practice is to use the Number type, as it can precisely handle decimal values and is convenient for performing calculations.

Schema Definition

When defining a Mongoose schema, you can define a price field as follows:

javascript
const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const productSchema = new Schema({
  name: String,
  price: {
    type: Number,
    required: true
  }
});

const Product = mongoose.model('Product', productSchema);

In this example, we create a product model with a required price field defined as the Number type. This means that data stored in the price field must be a number.

Note on Decimal Precision

While using Number facilitates storing and calculating prices, in JavaScript, the Number type is based on the IEEE 754 standard for double-precision floating-point numbers, which may introduce precision issues during complex mathematical operations. To avoid potential precision issues, some developers store prices using the smallest monetary unit (e.g., cents instead of dollars) or use specialized libraries such as decimal.js or bignumber.js for high-precision calculations.

Using Decimal128

Mongoose also supports the Decimal128 data type, which is based on MongoDB's decimal type. This type is particularly useful for financial calculations requiring high-precision decimals. If you decide to use the Decimal128 type, your schema definition would be slightly different:

javascript
const productSchema = new Schema({
  name: String,
  price: {
    type: mongoose.Schema.Types.Decimal128,
    required: true
  }
});

Using the Decimal128 type ensures high-precision decimal support at the database level, making it suitable for applications requiring precise financial calculations.

Conclusion

Overall, the most important aspect when storing price data is selecting the appropriate data type. For most applications, using the Number type is sufficient. However, if your application requires high-precision calculations, considering the Decimal128 type may be a better choice.