divideTwoNumbers()

Step 1: Define a function with two parameters

In the JavaScript language, we define a function using the keyword function, followed by the desired name of the function. For this example, we'll call the function divideTwoNumbers. The parameters will be the two numbers we want to divide - num1 and num2. These are defined within parentheses after the name of the function:

function divideTwoNumbers(num1, num2) {
}

Step 2: Adding error handling

Since we're dealing with division operation in our function which can result in a division by zero (undefined in mathematics), we want to ensure that our function can handle this case in a necessary way. In JavaScript, we can solve this by using an if statement which check whether the second number num2 is zero. If it is, we can make the function return a message indicating that division by zero is not allowed:

function divideTwoNumbers(num1, num2) {
    if (num2 === 0) {
        return "Error: Division by zero is not allowed.";
    }
}

Step 3: Perform the division

Now that we've addressed the error handling, let's proceed with the actual division operation. In JavaScript, division is done using the / operator. So, in our function, we want to return the result of dividing num1 by num2. We do this by using the return statement:

function divideTwoNumbers(num1, num2) {
    if (num2 === 0) {
        return "Error: Division by zero is not allowed.";
    }
    return num1 / num2;
}

Step 4: Test the function

Our function appears to be complete. However, it's always a good practice to test our function with some data to make sure it's working as expected. We can do this by calling the function with different pairs of values:

console.log(divideTwoNumbers(10, 2));  // Output: 5
console.log(divideTwoNumbers(5, 0));   // Output: Error: Division by zero is not allowed.

Conclusion:

In this post, we have walked through a step-by-step process of writing a JavaScript function to divide two numbers.This basic function also showcases how to handle edge cases, such as Division by zero to ensure that your function doesn't break when faced with exceptions. The full code implementation is as follows:

function divideTwoNumbers(num1, num2) {
    if (num2 === 0) {
        return "Error: Division by zero is not allowed.";
    }
    return num1 / num2;
}

console.log(divideTwoNumbers(10, 2));  // Output: 5
console.log(divideTwoNumbers(5, 0));   // Output: Error: Division by zero is not allowed.

This code will take two numbers and divide them, returning the result, unless the second number is zero, in such a case, it will return an error message.