The answer
Yes. Amazon asks candidates to implement a curried sum function that chains indefinitely. It tests understanding of currying, closures, function chaining, and JavaScript type coercion (if using toString).
Implement sum(1)(2)(3)(4)..(n) in JavaScript
Is sum(1)(2)(3) an Amazon interview question?
More FAQs in Implement sum(1)(2)(3)(4)..(n) in JavaScript
function sum(a) { return function(b) { if (b !== undefined) return sum(a + b); return a; }; }. Each call returns a function that accumulates. Call with no argument to get the result: sum(1)(2)(3)().
Two approaches: (1) call with no argument: sum(1)(2)(3)() - check if b !== undefined. (2) toString override: sum(1)(2)(3) + 0 - JavaScript calls toString when arithmetic is performed.
Currying and closures. Each call returns a function that closes over the accumulated sum. Without closures, the inner function would not have access to the previous arguments.
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