What are Promises in Node.js and how do they differ from callbacks?
Instruction: Explain the concept of Promises in Node.js and compare them with callback functions.
Context: This question assesses the candidate's understanding of asynchronous programming in Node.js, focusing on the use of Promises to manage asynchronous operations more effectively than callbacks.
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A callback is a function supplied for another operation to invoke. Node APIs often use an error-first callback convention, but callbacks can also be synchronous or invoked repeatedly, depending on the API.
A Promise represents an eventual result with pending, fulfilled or rejected state. It settles only once, and then/catch handlers compose later work through returned promises. Throwing in a handler rejects the promise it returns; returning another promise connects the result to that operation...