findSumCubesRange()

Step 1: Understand Problem Statement and Set Up Function

The first step towards finding the sum of cubes in a given range is understanding what's being asked in the problem statement. In this case, the function findSumCubesRange should take two parameters (let's call them start and end), and calculate the sum of the cubes of all the numbers in between these two parameters (including the start and end numbers).

Let's begin by setting up a skeleton function in JavaScript:

function findSumCubesRange(start, end) {
    // detail implementation will be written here.
}

Step 2: Validate Input

The next step is to validate the input by checking whether the start and end values are integers and the start is less than or equal to end. If one or both of these conditions are not met, then the function should return a message indicating an invalid input.

function findSumCubesRange(start, end) {
  if (!Number.isInteger(start) || !Number.isInteger(end)) {
  return "Invalid input. Please enter an integer number";
  }
  if (start > end) {
  return "Invalid range. End must be greater than start";
  }
}

Step 3: Initialize the Sum

We can initialize a variable sum that will contain the total sum of the cubes. It should be set to zero before the calculations begin.

function findSumCubesRange(start, end) {
  if (!Number.isInteger(start) || !Number.isInteger(end)) {
    return "Invalid input. Please enter integer numbers";
  }
  if (start > end) {
    return "Invalid range. End must be greater than start";
  }
  let sum = 0;
}

Step 4: Compute the Sum

In the fourth step, let's loop through all the numbers from start to end (inclusive). For each of these numbers, we will calculate their cube (i.e., the number multiplied by itself twice) and add that cube to sum.

function findSumCubesRange(start, end) {
  if (!Number.isInteger(start) || !Number.isInteger(end)) {
    return "Invalid input. Please enter integer numbers";
  }
  if (start > end) {
    return "Invalid range. End must be greater than start";
  }
  let sum = 0;
  for(let i = start; i <= end; i++) {
    sum += Math.pow(i, 3);
  }
}

Step 5: Return the Result

Finally, after the end of the loop, the sum variable will contain the total sum of the cubes of all the numbers in the passed range. Therefore, we should return this sum from our function.

function findSumCubesRange(start, end) {
  if (!Number.isInteger(start) || !Number.isInteger(end)) {
    return "Invalid input. Please enter integer numbers";
  }
  if (start > end) {
    return "Invalid range. End must be greater than start";
  }
  let sum = 0;
  for(let i = start; i <= end; i++) {
    sum += Math.pow(i, 3);
  }
  return sum;
}

Conclusion

In conclusion, the function findSumCubesRange takes a range of numbers (from start to end) and returns the sum of the cubes of all the numbers within this range. This process involves validating the input, initializing a sum variable, computing the sum of cubes within a loop, and finally returning the total sum. By following these steps, you can understand and implement this function in JavaScript effectively.