JS Quiz: Medium: Reduce accumulator initialization edge case

programming web dev
1

What happens here?

const arr = [];
const total = arr.reduce((sum, n) => sum + n);
console.log(total);
  • 0
  • undefined
  • NaN
  • TypeError
0 voters
2

JS Quiz answer: Option 4 (D).

Correct choice: TypeError

Why:
reduce on an empty array without an initial value throws TypeError.

Go deeper:

Arrays In JavaScript Temp

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3

Ngl I always forget this one and end up with a runtime error. it’s like the boss fight you keep thinking you’ve mastered.