# JavaScript: Calculate the sum of values in an array

## JavaScript Math: Exercise-17 with Solution

Write a JavaScript function to calculate the sum of values in an array.

Test Data :
console.log(sum([1,2,3]));
console.log(sum([100,-200,3]));
console.log(sum([1,2,'a',3]));
Output :
6
-97
6

Visual Presentation:

Sample Solution:

JavaScript Code:

``````// Define a function named sum that calculates the sum of an array of numbers.
function sum(input){
// Check if the input is an array, if not, return false.
if (toString.call(input) !== "[object Array]")
return false;

var total = 0;
// Iterate through the input array and sum the numeric elements.
for(var i = 0; i < input.length; i++) {
// If the element is not a number, skip to the next element.
if(isNaN(input[i])){
continue;
}
// Add the numeric value of the element to the total.
total += Number(input[i]);
}
// Return the total sum.
}

// Output the sum of the numbers in the array [1, 2, 3] to the console.
console.log(sum([1, 2, 3]));
// Output the sum of the numbers in the array [100, -200, 3] to the console.
console.log(sum([100, -200, 3]));
// Output the sum of the numbers in the array [1, 2, 'a', 3] to the console.
console.log(sum([1, 2, 'a', 3]));
```
```

Output:

```6
-97
6
```

Flowchart:

Live Demo:

See the Pen javascript-math-exercise-17 by w3resource (@w3resource) on CodePen.

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