Js reduce method ,why 0 at end?

Asked Dec 12 '22 at 07:08

Active Dec 12 '22 at 07:28

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Complete the square sum function so that it squares each number passed into it and then sums the results together. For example, for [1, 2, 2] it should return 9 because 1^2 + 2^2 + 2^2 = 9.

I managed to do the task but I did not understand why i had to add 0 at the end to pass the test. If i remove that 0,it doesn't pass. Can anyone please explain it ? I am newbie.

function numbers (numbers) {

return numbers.map((num) => num ** 2).reduce((initValue, currentValue) => initValue + currentValue,0)

}

edited Dec 12 '22 at 07:12

Jaromanda X

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asked Dec 12 '22 at 07:08

Onething-at-a-time

1

It's the initial `initValue`. Reading [the documentation](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce#syntax) is always useful. – Teemu Dec 12 '22 at 07:09
should work identically (in this case) without it though – Jaromanda X Dec 12 '22 at 07:10
4

@JaromandaX except if the array is empty. – VLAZ Dec 12 '22 at 07:13
sure, as I did say *in this case* where an array is being passed – Jaromanda X Dec 12 '22 at 07:13

Js reduce method ,why 0 at end?

0 Answers0