I recently had to do a test for a job interview, and the prompt was to code a function that returns the closest number to 0 given an array of negative and positive numbers.
My function works correctly but I heard back from the recruiter saying that my function is not very performant and that the readability was not great, here are the problem that they mentioned:
Performances à double check (filter + sort + for + push + reserve + shift, 4 identical call to Math.abs) Lack of readability ( 4 if / else if) I would like to know how I could have improved my function to make it more performant and more readable?
here's my function:
const closestToZero = (arr) => {
// 1-a variables:
let positiveNumbers = [];
let negativeNumbers = [];
// 1-b returns 0 if the input is either undefined or an empty array
if(typeof(arr) === 'undefined' || arr.length === 0) {
return 0
}
// 2- filter out non-number values then sort the array
const onlyNumbers = arr.filter(item => typeof(item) === 'number').sort((a,b) => a-b);
// 3- split the numbers into positive numbers and negative numbers
for(let i = 0; i < onlyNumbers.length; i++) {
if(onlyNumbers[i] > 0) {
positiveNumbers.push(onlyNumbers[i])
} else if (onlyNumbers[i] < 0) {
negativeNumbers.push(onlyNumbers[i])
}
}
// 4- reverse the negative array to get the closest to 0 at the first index
let reversedNegativeArray = negativeNumbers.reverse()
// 5- get rid of all the other values and keep only the closest to 0, if array empty return 0
let closestPositiveNumber = positiveNumbers.length > 0 ? positiveNumbers.shift() : 0
let closestNegativeNumber = reversedNegativeArray.length > 0 ? reversedNegativeArray.shift() : 0
// 6- Compare the result of the substraction of the closestPositiveNumber and the closestNegativeNumber to find the closestToZero
if(closestPositiveNumber - Math.abs(closestNegativeNumber) > 0 && closestNegativeNumber === 0 ) {
return closestPositiveNumber
} else if (closestPositiveNumber - Math.abs(closestNegativeNumber) < 0 && closestPositiveNumber === 0) {
return closestNegativeNumber
} else if(closestPositiveNumber - Math.abs(closestNegativeNumber) > 0) {
return closestNegativeNumber
} else if (closestPositiveNumber - Math.abs(closestNegativeNumber) <= 0) {
return closestPositiveNumber
}
}
requirements:
- if the closest number in input could be either negative or positive, the function returns the positive one
- if the input array is undefined or empty, the function returns 0
when input is [8, 5, 10] the function returns 5
when input is [5, 4, -9, 6, -10, -1, 8] the function returns -1
when input is [8, 2, 3, -2] the functions return 2