Conditional Writes DynamoDB: Expected params.ExpressionAttributeValues[':p'] to be a structure

Question

I'm trying to update my DynamoDB table using a conditional write, after read the official doc (https://docs.aws.amazon.com/amazondynamodb/latest/gettingstartedguide/GettingStarted.NodeJs.03.html#GettingStarted.NodeJs.03.05) I'm getting an error, I think this is a Syntax error, but I'm not sure, this is my code:

dynamodb.updateItem({
    dynamodb.updateItem({
    "TableName": "MyFavTable",
    "Key":{
        "MyFavKey": {
            "S": "MyFavKey"
            }
    },
    "UpdateExpression": "set MyLovelyBool=false",
    "ConditionExpression": "MyLovelyBool == :p",
    "ExpressionAttributeValues":{
        ":p":true
    }
}, function(err, data) {
 if (err) {
    console.error("Unable to update item. Error JSON:", JSON.stringify(err, null, 2));
 } else {
    console.log("UpdateItem succeeded:", JSON.stringify(data, null, 2));
 }
});

This run 'fine' by I get this error:

Unable to update item. Error JSON: {
"message": "Expected params.ExpressionAttributeValues[':p'] to be a     structure",
"code": "InvalidParameterType",
"time": "2016-10-22T14:48:42.961Z"
 }

I check if the json is valid and I was reading about ExpressionAttributeValues here (https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ExpressionPlaceholders.html#ExpressionAttributeNames) but I don't get info to resolve my problem.

Answer 1

Per the documentation, change this:

"ExpressionAttributeValues":{
        ":p":true
    }

To:

"ExpressionAttributeValues":{
        ":p": {"BOOL": true}
    }