Sometimes, we want to calculate average with the array reduce method in JavaScript.

In this article, we’ll look at how to calculate average with the array reduce method in JavaScript.

How to calculate average with the array reduce method in JavaScript?

To calculate average with the array reduce method in JavaScript, we can call reduce with a callback to return the partial sum of the average.

For instance, we write:

const array = [129, 139, 155, 176]
const average = array.reduce((avg, value, _, {
  length
}) => {
  return avg + (value / length);
}, 0);
console.log(average)

to call array.reduce with a callback that return avg + (value / length), which is the partial sum of the average so far.

The 2nd argument of 0 so the initial value of avg is 0.

Therefore, average is 149.75.

Conclusion

To calculate average with the array reduce method in JavaScript, we can call reduce with a callback to return the partial sum of the average.