Updating a Set in Dynamo db using Node Js - node.js

Question

I am trying to do one of the most simple operations "Update" in a dynamo db list.
Table Schema -
businessId : String, customers: StringSet, itemCode : NumberSet
I have an entry inserted via put -
bussinessId = "sampleBusiness", cuatomers 0: "cust1", itemCode 0: 4554
I want to add more items using update and here is what I have tried -
var updateRequest = {
'TableName' : tableName,
'Key' : {
'businessId' : {
"S" : businessId
}
},
'UpdateExpression' : "SET itemCode[2] =:attrValue",
'ExpressionAttributeValues' : {
':attrValue' : {
"N" : "564564"
}
}
};
This gives me error -
Document Path provided in document is invalid
I wanted to append new entries so tried this as well -
var sm = [];
sm[0] = "56465";
//Add business to
var updateRequest = {
'TableName' : tableName,
'Key' : {
'businessId' : {
"S" : businessId
}
},
'UpdateExpression' : 'SET #attrName = list_append(#attrName, :attrValue)',
'ExpressionAttributeNames' : {
'#attrName' : 'itemCode'
},
'ExpressionAttributeValues' : {
':attrValue' : {
"NS" : sm
}
}
};
This gives:
ValidationException: Invalid UpdateExpression: Incorrect operand type for operator or function; operator or function: list_append, operand type: NS
Also attempted this -
':attrValue' : {
"N" : "4564"
}
But same error.
As per the example provided in http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.Modifying.html , it adds a new element to the FiveStar review list. The expression attribute name #pr is ProductReviews; the attribute value :r is a one-element list. If the list previously had two elements, [0] and [1], then the new element will be [2].
SET #pr.FiveStar = list_append(#pr.FiveStar, :r)
which Says :r is one element list
I am missing some thing here. Request if any one can help. Struck on this for long time. I just want to append elements in set in dynamo db using nodeJS.

Answer 1

It looks like this:
'ExpressionAttributeValues' : {
':attrValue' : {
"NS" : sm
}
}
Should be this:
'ExpressionAttributeValues' : {
':attrValue' : {
"S" : sm
}
}
Or you need to cast this value sm[0] = "56465"; to a Number Number("56465") and change the :attrValue data type "S" to "N". Depends on how you have your table configured.
It's possible too that you should assign :attrValue to be "S" : sm[0] because right now you are passing an "S" a whole array.

Answer 2

I got a proper solution
var item = {"endTime": "7pm", "imageName": "7abcd", "startTime": "7pm"};
dynamo.updateItem({
TableName:'TableName',
Key:{"BucketName":"abcdefg" },
UpdateExpression : "SET #attrName = list_append(#attrName, :attrValue)",
ExpressionAttributeNames : {
"#attrName" : "ImageLists"
},
ExpressionAttributeValues : {
':attrValue' : [item]
}
},function(err, data) {
if (err)
console.log(err);
else
console.log(data)
});