Is there a good object mapper for Amazons dynamodb(through aws sdk) which can be used in nodejs?

Question

Maybe the question does not apply to dynamoDB due to it not being Relational Db. However, I'm looking for a good object mapper which can be used in nodejs and aws sdk to map existing model classes to dynamoDB tables. Does anyone have experience with this issue/question, or have you used such a module/library?

Answer 1

If you are looking for schema:

• https://github.com/clarkie/dynogels (well supported forked from vogels which has been abandoned )
• https://github.com/automategreen/dynamoose (inspired by Mongoose )

If you are looking for something to throw javascript objects (even circular graphs) to:

• https://github.com/aaaristo/dyngodb (alpha)
• https://github.com/aaaristo/angular-gson-express-dyngodb

dyngodb has experimental support for full-text search, and transactions too.

Both are based on aws-sdk.

Answer 2

Also worth considering is simple marshallers, which just translate between the dynamoDB format and regular js objects or JSON.

DynamoDb-Data-Types
https://github.com/kayomarz/dynamodb-data-types
https://www.npmjs.com/package/dynamodb-data-types

"This utility helps represent AWS DynamoDb data types. It maps (marshalls) JavaScript data into the format required by DynamoDb."

dynamoDb-marshaler
https://github.com/CascadeEnergy/dynamoDb-marshaler https://www.npmjs.com/package/dynamodb-marshaler

"Translates sane javascript objects (and JSON) into DynamoDb format and vice versa." [does not support B type.]

Update 2016-06 :
Just discovered that the AWS SDK now does this for you. Their documentation is only partially converted so I guess this is a recent addition. Read about it here .

But these marshallers are still useful because there are circumstances where you can't use the new document client, eg. when processing a dynamoDB stream.

Answer 3

You could also try: https://dynamoosejs.com/ . It is inspired by mongoose again.

Answer 4

If you are using Typescript, dynamo-easy might be a good option. Just add some decorators to your model and start using it.

import { Model, PartitionKey, DynamoStore } from '@shiftcoders/dynamo-easy'

@Model()
export class Person {
  @PartitionKey()
  id: string
  name: string
  yearOfBirth: number
}

const personStore = new DynamoStore(Person)

personStore
  .scan()
  .whereAttribute('yearOfBirth').equals(1958)
  .exec()
  .then(res => console.log('ALL items with yearOfBirth == 1958', res))

It uses the AWS DynamoDB sdk but takes care of the mapping between JS and DynamoDB types and provides a simple to use fluent API.

full disclosure: I am one of the authors of this library

Answer 5

After looking over all the posts I landed on https://github.com/awspilot/dynamodb-oop

It doesn't hide the API but instead just wraps it in a nice, fluent way with promises even and you inject your version of the aws-sdk. It's similar to dynamodb-data-types but also wraps the methods too (not just the data types).

Extra bonus, the same author has https://github.com/awspilot/dynamodb-sql Didn't use the sql wrapper but I can see how some people may prefer that.

Dynamoose is obviously inspired by mongoose and is a good choice if you have a well-defined schema and/or want to be abstracted away from the DynamoDB details.

Answer 6

Have you seen dynasaur ? It seems to be the type of thing you're looking for, but I have not used it myself. There's also dynamodb-data-types which is not an ORM, but makes it easy to convert to/from standard JavaScript objects.