calculateArraySum()

Step 1: Creating a function

We start by creating a function named 'calculateArraySum' which would take in an array as a parameter. This function would be responsible for processing the input array and returning the sum of all the numbers.

function calculateArraySum(myArray) { 
   // code to calculate the sum 
}

Step 2: Variable initialization

Inside the function, declare a variable named 'sum' and initialize it to zero. This variable will hold the running total of the numbers in the array as we iterate through the array elements.

function calculateArraySum(myArray) { 
   let sum = 0;
   // loop to iterate over the array 
}

Step 3: Iterating through the array

Next step is to traverse through the array. We use a 'for' loop for this purpose. The loop would iterate over each element present in the array.

function calculateArraySum(myArray) { 
   let sum = 0;
   for(let i = 0; i < myArray.length; i++) {  
       // adding array elements to the sum
   }
}

Step 4: Adding array elements to the sum

Inside the loop, we add the current element of the array to the 'sum' variable. This step will be repeated for each element of the array.

function calculateArraySum(myArray) { 
   let sum = 0;
   for(let i = 0; i < myArray.length; i++) {  
       sum = sum + myArray[i];
   }
}

Step 5: Return the Sum

Once all the elements of the array have been added, the loop ends. At this point, sum holds the total of all array elements. Finally, we return this value from our function.

function calculateArraySum(myArray) { 
   let sum = 0;
   for(let i = 0; i < myArray.length; i++) {  
       sum = sum + myArray[i];
   }
   return sum;
}

Conclusion

Our 'calculateArraySum' function is now complete. This function takes in an array of numbers, iterates through each element, and returns the sum total of all the elements in the array. Always remember, JavaScript arrays are zero-based, which means the first element of the array is accessed with the number 0. So, our loop starts from 0 (let i = 0) and runs until it has gone through every element (i < myArray.length).