MIGRATION ISSUE: Undocumented change in the behaviour of DynamoDB marshalling

[andrejleitner]

Pre-Migration Checklist

• [X] I've read the Migration Guide.
• [X] I've reviewed the upgrading notes and major version differences mentioned in UPGRADING.md.
• [X] I've checked AWS Forums and StackOverflow for similar migration issues.

Which JavaScript Runtime is this issue in?

Node.js (includes AWS Lambda)

AWS Lambda Usage

• [X] Yes, my application is running on AWS Lambda.
• [X] No, my application is not running on AWS Lambda.

Describe the Migration Issue

It appears that version 2 automatically omitted undefined values. To restore this "feature" in version 3, the removeUndefinedValues option must be set. I did not find this mentioned in the migration guide or notes.

Code Comparison

import { DynamoDB } from 'aws-sdk';
import { marshall } from '@aws-sdk/util-dynamodb';

const sample = {
    foo: 'test',
    bar: undefined,
};
console.log('sample', sample);

const marshalledV2 = DynamoDB.Converter.marshall(sample);
console.log('marshalledV2', marshalledV2);

const marshalledV3 = marshall(sample, { removeUndefinedValues:true });
console.log('marshalledV3', marshalledV3);

Observed Differences/Errors

• removeUndefinedValues option not set:

❯ pnpm ts-node asd.ts
sample { foo: 'test', bar: undefined }
marshalledV2 { foo: { S: 'test' } }
~/.../@aws-sdk/util-dynamodb/dist-cjs/index.js:99
  throw new Error(`Pass options.removeUndefinedValues=true to remove undefined values from map/array/set.`);
...

• removeUndefinedValues set to true:

❯ pnpm ts-node asd.ts
sample { foo: 'test', bar: undefined }
marshalledV2 { foo: { S: 'test' } }
marshalledV3 { foo: { S: 'test' } }

Additional Context

https://github.com/aws/aws-sdk-js-v3/issues/1816 https://github.com/aws/aws-sdk-js-v3/pull/1840

[RanVaknin]

Hi @andrejleitner ,

Thanks for bringing this up. We will add it to the migration guide.

All the best, Ran~

[u11d-michal-miler]

So here is the solution: https://github.com/aws/aws-sdk-js-v3/blob/main/UPGRADING.md#undefined-values-in-when-marshalling

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