Checking for claims in the identity object - AppSync with Lambda

main.ts

// To man manually check for groups, you can get the user's identity from
// the event.identity object, and check for claims in
// the event.identity.claims['cognito:groups']

function checkForGroup(event:AppSyncEvent, groupName:string) {
  if (event.identity) {
    if (event.identity.claims['cognito:groups']) {
      if (event.identity.claims['cognito:groups'].includes(groupName)) {
        return true
      }
    }
  }
  return false
}