Flutter aws amplify not returning data when calling graphql api - amazon-web-services

Question

On button click I have programmed to call a graphql api which is connected to a Lambda function and the function is pulling data from a dynamodb table. The query does not produce any error, but it doesn't give me any results as well. I have also checked the cloudwatch logs and I dont see any traces of the function being called. Not sure on the careless mistake I am making here.
Here is my api
void findUser() async {
try {
String graphQLDocument = '''query getUserById(\$userId: ID!) {
getUserById(userId: \$id) {
id
name
}
}''';
var operation = Amplify.API.query(
request: GraphQLRequest<String>(
document: graphQLDocument,
variables: {'id': 'USER-14160000000'}));
var response = await operation.response;
var data = response.data;
print('Query result: ' + data);
} on ApiException catch (e) {
print('Query failed: $e');
}
}
Here is my lambda function -
const getUserById = require('./user-queries/getUserById');
exports.handler = async (event) => {
var userId = event.arguments.userId;
var name = event.arguments.name;
var avatarUrl = event.arguments.avatarUrl;
//console.log('Received Event - ', JSON.stringify(event,3));
console.log(userId);
switch(event.info.fieldName) {
case "getUserById":
return getUserById(userId);
}
};
const AWS = require('aws-sdk');
const docClient = new AWS.DynamoDB.DocumentClient({region: 'ca-central-1'});
async function getUserById(userId) {
const params = {
TableName:"Bol-Table",
KeyConditionExpression: 'pk = :hashKey and sk = :sortKey',
ExpressionAttributeValues: {
':hashKey': userId,
':sortKey': 'USER'
}
};
try {
const Item = await docClient.query(params).promise();
console.log(Item);
return {
id: Item.Items[0].pk,
name: Item.Items[0].details.displayName,
avatarUrl: Item.Items[0].details.avatarUrl,
createdAt: Item.Items[0].details.createdAt,
updatedAt: Item.Items[0].details.updatedAt
};
} catch(err) {
console.log("BOL Error: ", err);
}
}
module.exports = getUserById;
Upon button click I get this

Answer 1

Moving my comment to an answer:
Can you try changing your graphQLDocumnet to
String graphQLDocument = '''query getUserById(\$id: ID!) {
getUserById(userId: \$id) {
id
name
}
}''';
Your variable is $userId and then $id. Try calling it $id in both places like in your variables object.

Answer 2

Your flutter code is working fine but in lambda from the aws is returning blank string "" to not to print anything