Get matched range value from array javascript

Question

I have one array which is named as range and one lookpup variable. Now I am trying to get the matched range value from my range array. I tried to reduce method but it gives me an unexpected ouput.

Actual output

• My value is 51 then it returns me 100

Expected output

• Ex 1 - My value is 51 it's between 0-100 it should return 0 Ex 2 - My value is 135 it's between 100-150 it should return 100

My code

var lookup = 51; 
var range = [0, 100, 150, 200, 300, 300.2];
let filtered = range.reduce((prev, curr) => Math.abs(curr - lookup) < Math.abs(prev - lookup) ? curr : prev);
console.log(filtered); //100

Not Working in this case

const lookup = 201; 
const range = [200, 250, 300, 0, 450, 898].reverse();
const result = range.find(num => num <= lookup);
console.log(result); //0

Answer 1

Your desired result is a single number from the range array, so you should use .find instead of .reduce. Iterate from the right, and return true for the first element being iterated over that's smaller than or equal to the lookup.

const lookup = 51; 
const range = [0, 100, 150, 200, 300, 300.2].reverse();
const result = range.find(num => num <= lookup);
console.log(result);

If the array isn't necessarily sorted first, then sort it.

const lookup = 201; 
const range = [200, 250, 300, 0, 450, 898].sort((a, b) => b - a);
const result = range.find(num => num <= lookup);
console.log(result);