How to Add All Numbers in an Array in JavaScript

Adding all numbers in an array is a common task in JavaScript. Whether you're working with a list of values or need to compute a total, there are various methods you can use to sum the elements of an array. In this article, we'll explore different ways to add all the numbers in an array using JavaScript.

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1. Using a for Loop

The most straightforward way to sum all the numbers in an array is by using a for loop. This method involves iterating through each element in the array and adding it to a running total.

function sumArray(numbers) {
  let total = 0;
  for (let i = 0; i < numbers.length; i++) {
    total += numbers[i];
  }
  return total;
}

const numbers = [1, 2, 3, 4, 5];
console.log(sumArray(numbers)); // Output: 15

In this example, the sumArray function iterates through the numbers array, adds each number to the total variable, and returns the sum.

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2. Using the reduce Method

The reduce method is a more functional approach to summing the elements in an array. It applies a function against an accumulator and each element in the array (from left to right) to reduce it to a single value.

const numbers = [1, 2, 3, 4, 5];
const total = numbers.reduce((accumulator, currentValue) => accumulator + currentValue, 0);
console.log(total); // Output: 15

Here, the reduce method starts with an initial value of 0 and adds each element in the array to the accumulator, resulting in the total sum of the array elements.

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3. Using forEach Loop

Another method to sum the numbers in an array is by using the forEach loop. This method involves calling a function for each element in the array and adding each element to a running total.

function sumArray(numbers) {
  let total = 0;
  numbers.forEach((number) => {
    total += number;
  });
  return total;
}

const numbers = [1, 2, 3, 4, 5];
console.log(sumArray(numbers)); // Output: 15

The sumArray function in this example uses forEach to iterate over each element in the numbers array, adding them to the total variable.

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4. Using a for...of Loop

The for...of loop provides a simpler syntax for iterating over arrays in JavaScript. You can use this loop to sum the elements in an array as well.

function sumArray(numbers) {
  let total = 0;
  for (let number of numbers) {
    total += number;
  }
  return total;
}

const numbers = [1, 2, 3, 4, 5];
console.log(sumArray(numbers)); // Output: 15

In this example, the sumArray function uses the for...of loop to iterate through each number in the array and add it to the total.

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5. Conclusion

There are multiple ways to sum all numbers in an array in JavaScript, including using a for loop, the reduce method, forEach loop, and the for...of loop. Each method has its own benefits, and you can choose the one that best fits your needs and coding style.