In this tutorial we learn Two types of Sum Of An Array In JavaScript

  1.  Use the for Loop to Sum an Array in a JavaScript
  2. Use the reduce() Method to Sum an Array in a JavaScript

Ex. 1 - Use the for Loop to Sum an Array

The for loop is used to sum an array. We can use it to add all the numbers in an array and store it in a variable.

<script>
const array = [1, 2, 3, 4, 5];
let sum = 0;

for (let i = 0; i < array.length; i++) {
    sum += array[i];
}
console.log(sum);
</script>


Ex. - 2. Use the reduce() Method to Sum an Array

Use the reduce() function to find or calculate the sum of an array of numbers. 

  <script>
    var array = [1, 2, 3, 4, 5];
    
    // Getting sum of numbers
    var sum = array.reduce(function(a, b){
        return a + b;
    }, 0);
    
    console.log(sum);
</script>

I hope it can help you...