Add two consecutive elements from the original array and display the result in a new array with JavaScript

We are required to write a JavaScript function that takes in an array of Numbers and returns a new array with elements as the sum of two consecutive elements from the original array.

For example, if the input array is:

const arrayOne = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];

Then the output should be:

const newArrayOne = [1, 5, 9, 13, 17]

Let's write the code for this function:

Example

const arrayOne = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];

const doubleSum = arr => {
    const res = [];
    for(let i = 0; i 

Output

The output in the console will be:

[ 1, 5, 9, 13, 17 ]


How It Works

The function works by iterating through the array with a step of 2 (i += 2). For each iteration, it adds the current element arr[i] to the next element arr[i+1]. The || 0 ensures that if there's no next element (for odd-length arrays), it adds 0 instead of undefined.

Handling Odd-Length Arrays

const oddArray = [1, 2, 3, 4, 5];
console.log(doubleSum(oddArray));


[ 3, 7, 5 ]


In this case, the last element (5) has no pair, so it's added to 0, resulting in 5.

Conclusion

This approach efficiently creates a new array by summing consecutive pairs of elements. The loop increment of 2 ensures we process every pair, while the || 0 handles odd-length arrays gracefully.