How to translate Decimal128 values over Rest

Question

I'm using Mongoose as part of a package , saving heaps of time.

The package I am using is https://github.com/florianholzapfel/express-restify-mongoose. When I query Mongodb , and I have a Decimal128 type , it returns those values like this:

{
    "sku": "shGHYB12-60-LOZ",
    "name": "Prd",
    "size": "60",
    "buyPrice": {
        "$numberDecimal": "12.55"
    }
}

Which is fine when it's in a Mongoose object , but when I expose it over the Rest API ( this package uses restify ) , it is just a json representation.

If I post it back through the REST Api in a Patch or Put request - just as a string or number ( see below ) , it works fine and stores it in the database correctly translating it using the Mongoose model.

{
    "sku": "shGHYB12-60-LOZ",
    "name": "Prd",
    "size": "60",
    "buyPrice": "12.5995"
}

The Part of my mongoose model is like this

"buyPrice": {
    "type": "Decimal"
}

How can I store it as a decimal type in MongoDb but expose it as a number over REST? I'm just not sure how to go about it.

The 3 areas it could happen I guess are

1. The Mongoose model
2. Restify
3. Some sort of "hook" in Mongoose.

I'm not overly familiar with either. Thanks for your time.

Demythologize

You could massage the data structure a little bit before you send it out (maybe in the controller or better yet by creating a model wrapper function). Use parseFloat("1.23") to turn the string representation into a float. – Undercast

@Undercast the whole point of Decimal128 is to avoid the float type. – Demythologize

A float is a decimal. Your question might need some clarification. – Undercast

@Undercast I hope these will help you understand the difference. net-informations.com/q/faq/float.html , api.mongodb.com/python/3.4.0/api/bson/decimal128.html . This is why I am referring to Decimal128 , which solves the rounding issues with the float type. If you have something that will help me then please post an answer , otherwise please just let it rest! Thanks. – Demythologize

@MartinThompson were you able to figure it out? All the answers I got are converting back to Float and not Decimal128. – Skid

Answer 1

Make a helper function before declaring a schema:

   function getMoney(value) {
      if (typeof value !== 'undefined') {
         return parseFloat(value.toString());
      }
      return value;
    }

Add a getter to your field like this:

price: {
      type: Schema.Types.Decimal128,
      get: getMoney
    },

Schizogony

I also though of the same idea, but this doesn't seem to work for me – Mayers