DynamoDB Scan, Error in ExpressionAttributeValues Unexpected Key NodeJS

Question

I'm trying to do a Scan to my DynamoDB table in NodeJS, but I'm having trouble with ExpressionAttributeValues because don't recognize the placeholder I defined in the filter expression. I pass as paremeter an object with the information I want, but sends me this error:

"Unexpected Key ':Value' found in params.ExpressionAttributeValues['atributeValues'], "code":"Unexpected parameter"

I don't know what's happening because if I put the content of the object as parameter it works perfectly so I'm stucked.

function Consult(cb, Filter, Event){
  var filterExpression = Filter+"= :Value";
  if(typeof Event[Filter] == "string"){
    //This is the object I'm trying to pass as parameter
    var attributeValues = {
      ":Value" : {"S" : Event[Filter] }
    }
  }else {
    //This is the object I'm trying to pass as parameter
    var attributeValues = {
      ":Value" : {"N" : Event[Filter] }
    }
  }
  dynamodb.scan({
      TableName: tableName,
      FilterExpression: filterExpression,
      ExpressionAttributeValues:{ ":Value" : {"S" : Event[Filter] } } //This Works
      ExpressionAttributeValues:{ attributeValues } //This don't and I don't know why
  }, function(err, data){
      if(err){
          console.log(err);
          cb(err, null);
      } else {
          cb(null, data.Items);
      }
  });
}

FilterExpression: 'contains(#postid,:val)', ExpressionAttributeNames: { '#emmp': 'postId' }, ExpressionAttributeValues: { ':val': { 'S': postid } } — arjun kori
– arjun kori, Commented Sep 14, 2016 at 13:54

notionquest · Accepted Answer · 2016-09-14 13:33:00Z

3

Please change the code as mentioned below. No need to wrap the attributeValues with curly braces again.

ExpressionAttributeValues: attributeValues

answered Sep 14, 2016 at 13:33

notionquest

39.4k6 gold badges120 silver badges112 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Camarbro Over a year ago

Oh man. Thanks for the time. I didn't check the answer until today, I solved it just the way you did. Appreciate it

Peter Fennema · Accepted Answer · 2016-09-14 09:10:03Z

-1

This is not a direct answer (I can't share formatted code in a comment), but a suggestion how to debug this:

var params = {};
params.TableName = tableName;
params.FilterExpression = filterExpression;
params.ExpressionAttributeValues = { attributeValues };
console.log(JSON.stringify(params));
dynamodb.scan(params, function(err, data){
....
}

The output of the console.log will show you exactly the parameters for the scan. You can compare both alternatives for ExpressionAttributeValues. This will give you a hint about what's wrong.

answered Sep 14, 2016 at 9:10

Peter Fennema

1,71012 silver badges14 bronze badges

Collectives™ on Stack Overflow

DynamoDB Scan, Error in ExpressionAttributeValues Unexpected Key NodeJS

2 Answers 2

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related