[BUG] `saveUnknown` doesn't work for nested properties of Arrays

Summary:

It appears that if you use the saveUnknown property for a subfield of an Array entry, undeclared fields are not actually persisted. In the example below, the following is saved and properties e and f are erased:

{
  a: 2,
  b: [{
    c: 'foo',
    d: {}
  }]
}

The only way I could get around this was enabling saveUnknown: true at the top-level schema (ie, the second argument to schema in the example below). This doesn’t really seem ideal because you’re now opening up the schema to unexpected top-level fields that aren’t supposed to be saved.

Code sample:

Schema

const nested = new dynamoose.Schema({}, { saveUnknown: true })
const schema = new dynamoose.Schema({
  a: Number,
  b: { 
    type: Array,
    schema: [{
      type:Object,
      schema: { c: String, d: nested }
    }]
  }
})

Model

const obj = {
  a: 2,
  b: [{
    c: 'foo',
    d: {
      e: 1,
      f: 'bar'
    }
  }]
}

General

schema.create(obj)

Current output and behavior (including stack trace):

Expected output and behavior:

Environment:

Operating System: Operating System Version: Node.js version (node -v): NPM version: (npm -v): Dynamoose version:

Other information (if applicable):

Other:

• I have read through the Dynamoose documentation before posting this issue
• I have searched through the GitHub issues (including closed issues) and pull requests to ensure this issue has not already been raised before
• I have searched the internet and Stack Overflow to ensure this issue hasn’t been raised or answered before
• I have tested the code provided and am confident it doesn’t work as intended
• I have filled out all fields above
• I am running the latest version of Dynamoose

[fishcharlie]

Thanks for the report. I was able to reproduce this. Will work on fixing as soon as I can.

---

For personal reference, MCVE below. The issue is that the saveUnknown variable is including schema properties, when it shouldn’t be.

const dynamoose = require("dynamoose");

(async () => {
	dynamoose.aws.ddb.local();

	const nested = new dynamoose.Schema({"random": String}, { saveUnknown: true })
	const schema = new dynamoose.Schema({
		a: Number,
		b: {
			type: Array,
			schema: [{
				type: Object,
				schema: { c: String, d: nested }
			}]
		}
	});

	const Model = dynamoose.model(`Test-${Date.now()}`, schema);

	const obj = {
		a: 2,
		b: [{
			c: 'foo',
			d: {
				e: 1,
				f: 'bar'
			}
		}]
	}

	await Model.create(obj);

	console.log(JSON.stringify((await Model.scan().exec()).toJSON(), null, 4));
})();

[manh-vv]

I got the same issue. I workaround by adding one more simple field to the document. Ex: The below document will not be saved.

{
  "id": "d1",
  "tx": [{ "object1": "value1" }]
}

but this will work, of course, saveUnknown: true

{
  "id": "d1",
  "ttl": -1,
  "tx": [{ "object1": "value1" }]
}