sum(1)(2)(3) Interview Tips for Amazon

sum(1)(2)(3) Interview Tips for Amazon

Tips

1. Recognize it as currying: the question tests currying and closures.
2. Start with the simple solution: terminate with an empty call.
3. Explain how closures work: each returned function closes over the accumulated sum.
4. Mention toString as an alternative: shows deeper JavaScript knowledge.
5. Handle the follow-up: support multiple arguments with rest params.

Step-by-Step Approach

1. Identify that each call returns a function (currying).
2. The function needs to accumulate the sum (closure).
3. It needs a way to terminate (empty call or toString).
4. Write the basic solution.
5. Explain how it works step by step.
6. Handle follow-up questions (multiple args, other operations).

Common Mistakes

1. Not returning a function: forgetting to return the inner function.
2. Not accumulating: losing the previous value.
3. No termination: no way to get the final result.
4. Overcomplicating: trying to use a class or complex state management.

The Takeaway

For the Amazon sum question: recognize currying, start with the empty-call solution, explain closures, mention toString as an alternative, and handle follow-ups (multiple args). Common mistakes: not returning a function, not accumulating, no termination, overcomplicating.