How to add number to Number Set in DynamoDB

AWS.DynamoDB.DocumentClient does not provide a way to add number to Number Set.
Need to use lower api Class: AWS.DynamoDB — AWS SDK for JavaScript.

I've tried few times and figured out the sytax of ADD operaion which is not desctibed in UpdateItem reference. Just put ADD, column name and value.

See Modifying Items and Attributes with Update Expressions - Amazon DynamoDB for ADD syntax.

Following code appends given numbers without making dupes.

dynamodb.updateItem({
  "TableName" : "mytable",
  "Key" : {
    "Id": {"S": uuid},
  },
  "UpdateExpression" : "ADD setname :valuesToAdd",
  "ExpressionAttributeValues" : {
    ": valuesToAdd" : { "NS": ["440"] }
  },
  ReturnValues:"UPDATED_NEW"
});

Refs

• node.js - How to update an item in Dynamodb of type String Set (SS)? - Stack Overflow
• UpdateItem - Amazon DynamoDB