# Sum of numbers from 1 to n JavaScript recursion | Example code

You don’t need to loop through each pair and add them in recursion. Just use if statement as below example.

## Sum of numbers from 1 to n Examples in JS

Let’s see HTML example code:-

### Sum of numbers from 1 to n JavaScript recursion

Check the value and if truthy return `n` plus the sum of `n - 1`

if the value is smaller than one and returns zero in this case, otherwise the result of the actual value plus the result of calling sum function with a decrement value.

``````<!DOCTYPE html>
<html>
<body>

<script type="text/javascript">
function sum(n) {
if (n < 1) return 0;
return n  + sum(n - 1);
}

console.log(sum(3));
</script>

</body>
</html>``````

Output:

### Without Recursion Example code

Adding numbers between one and a given number without recursion in JavaScript:-

``````<!DOCTYPE html>
<html>
<body>

<script type="text/javascript">
function sumNums (num) {
let array = [];
for (let i = 0; i <= num; i++) {
array.push(i);
}
return array.reduce((a, b) => a + b);
}

console.log(sumNums(10));

</script>

</body>
</html>``````

Output:

Do comment if you have any doubts and suggestion on this topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.

OS: Windows 10

Code: HTML 5 Version

This site uses Akismet to reduce spam. Learn how your comment data is processed.