# Get the Index of the Max Value of an Array in JavaScript

Updated onbyAlan Morel

When you are working with arrays, especially arrays of numbers, you sometimes want to know where the highest value is.

To do this, you'll have to first find the highest value in the array, then find the index of that value.

In this post, we'll learn how to get the index of the highest value of an array in JavaScript.

## How to get the index of the highest value of an array

To begin, let's start off with our example array of random numbers from 1 to 100:

``````JAVASCRIPTconst array = [4, 25, 37, 54, 73, 83, 21, 42];
``````

To get the index of the highest value of an array, we first must find the highest value in the array.

We can do this by using the `Math.max` function and pass it the deconstructed array:

``````JAVASCRIPTconst array = [4, 25, 37, 54, 73, 83, 21, 42];

const highestValue = Math.max(...array);

console.log(highestValue);
``````
``````BASH83
``````

Now that we have the highest value in the array, we just need to find the index of that value.

We can do this by using the built-in `Array.indexOf()` function and passing it the highest value:

``````JAVASCRIPTconst array = [4, 25, 37, 54, 73, 83, 21, 42];

const highestValue = Math.max(...array);
const highestValueIndex = array.indexOf(highestValue);

console.log(highestValueIndex);
``````
``````BASH5
``````

## Conclusion

In this post, we learned how to get the index of the highest value of an array.

Simply use the `Math.max()` function to get the highest value, then use the `Array.indexOf()` function to get the index.