feat(parser): DynamoDBMarshalled helper to parse DynamoDB data structure

[arnabrahman]

Summary

When working with Amazon DynamoDB Stream events, the service sends the DynamoDB items in the database-specific format rather than regular JSON objects.

For example, a string might be represented as { "S": "foo" } rather than just foo. This makes parsing the actual changes within an event hard to parse and validate since it requires customers writing a Zod schema with this in mind.

This PR introduces a helper function DynamoDBMarshalled to work this structure

Changes

• Helper function to unmarshall and validate dynamoDB stream schema
• New helper function is exported to a subpath
• Unit test the new helper function
• Write up the docs for the new helper function

Issue number: #3194

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Disclaimer: We value your time and bandwidth. As such, any pull requests created on non-triaged issues might not be successful.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[arnabrahman]

I would appreciate suggestions on using this type.

Setting the type to unknown causes a TypeScript error. The @aws-sdk/util-dynamodb package has a peer dependency on @aws-sdk/client-dynamodb and we are using the AttributeValue type from @aws-sdk/client-dynamodb. Should we also declare @aws-sdk/client-dynamodb as a peer dependency?

Alternatively, we could set the type to unknown and suppress the TypeScript error using biome-ignore, though I would prefer to avoid this approach.