Description

By default when an dynamo object is unmarshalled, sets are converted to native javascript sets.

This is fine for some use cases, however for other cases that rely on JSON.stringify whether its for an API call or mapping somewhere else sets are converted to undefined in this process.

This change gives the ability to override the usage of sets and prefer to use native arrays. I am not sure if this name is perfect but also up for anything here.

Syntax

const input = {
 NS: [1,2,3,4]
};

// without option
const obj = unmarshall(input)
// Output - new Set() {1,2,3,4}

// with option enabled
const obj = unmarshall(input, { preferNativeArrays: true})
// Output - [1,2,3,4]

Testing

Unit tests updated to account for use case.

Additional context

Some alternatives that I have used in the past for this are to manually clone deep with the modification like below.

import cloneDeepWith from 'lodash.clonedeepwith'

cloneDeepWith(unmarshall(record.dynamodb!.NewImage! as never), (val: unknown) => {
          // Sets dont stringify at all. Thanks AWS
          if (val instanceof Set) {
            return [...val];
          }
        });

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