I posted this request one or two months ago and I want to request for front end chanllenges on leetcode again. Also I am going to post some possible front end coding questions that an interviewer would ask:\n```\nImplement (Javascript):\nPromise\nPromise with limit\nPromise.all\nquerySelector\nEvenEmitter\nObservable\nFlat array\nGiven two identical DOM tree structures, A and B, and a node from A, find the corresponding node in B.\n\n\nImplement (Util function)\nDebounce\nThrottle.\nMemoize\nRetry\n```

I posted this request one or two months ago and I want to request for front end chanllenges on leetcode again. Also I am going to post some possible front end c