ABCD questions

• Graphql returning Cannot return null for non-nullable field Query.getDate. As I am new to graphql I want to know is my approach is wrong or my code?
• How could I generate temporary credentials using Cognito Identity pool for accessing aws services?
• How to get API gateway url in AWS lambda function?
• Elasticsearch object mapping for tried to parse field [null] as object, but found a concrete value

ABCD answers