Get Indexes of Highest and Lowest Items of a JavaScript Array

You can use the for loop to find the indexes of the highest and lowest numbers in a JavaScript array.

          let numbers = [5, 2, 9, 7, 1, 3, 8]

let maxIndex = 0
let minIndex = 0

for (let i = 1; i < numbers.length; i++) {
    // Get index of the highest item
    if (numbers[i] > numbers[maxIndex]) {
        maxIndex = i
    }

    // Get index of the lowest item
    if (numbers[i] < numbers[minIndex]) {
        minIndex = i
    }
}

console.log(maxIndex) // 2

console.log(minIndex) // 4

        

Explanation

Here I have an array of numbers. I want to get the indexes of the highest and lowest number of that array.

Let's declare 2 variables to store the index values.

You have to use the for loop to iterate over the array of numbers. Because inside the for loop, it will be easy to find the highest and lowest values.

Get Index of The Highest Number

Inside the for loop, check if the current element numbers[i] is greater than the element at the index maxIndex in the array.

If it is greater, then reassign the maxIndex variable with the current index (i) value.

Get Index of The Lowest Number

Inside the for loop, check if the current element numbers[i] is lower than the element at the index maxIndex in the array.

If it is lower, then reassign the minIndex variable with the current index (i) value.

After finishing the loop, if you check the maxIndex and minIndex variables, you will get the indexes of the highest and lowest numbers of that array.