Suppose we have an array like this −
const arr = [2, 42, 82, 122, 162, 202, 242, 282, 322, 362];
We are required to write a JavaScript function that takes in one such array and a number, say n.
The function should return the index of item from the array which is closest to the number n.
Therefore, let’s write the code for this function −
Example
The code for this will be −
const arr = [2, 42, 82, 122, 162, 202, 242, 282, 322, 362];
const closestIndex = (num, arr) => {
let curr = arr[0], diff = Math.abs(num - curr);
let index = 0;
for (let val = 0; val < arr.length; val++) {
let newdiff = Math.abs(num - arr[val]);
if (newdiff < diff) {
diff = newdiff;
curr = arr[val];
index = val;
};
};
return index;
};
console.log(closestIndex(150, arr));Output
The output in the console will be −
4