Cell 1

// definition for nodejs

What the code could have been:

// Import required modules
const console = require('console');

/**
 * Calculates the sum of two numbers.
 *
 * @param {number} a - The first number.
 * @param {number} b - The second number.
 * @returns {number} The sum of a and b.
 */
function addNumbers(a, b) {
    return a + b;
}

/**
 * Subtracts b from a.
 *
 * @param {number} a - The first number.
 * @param {number} b - The second number.
 * @returns {number} The difference between a and b.
 */
function subtractNumbers(a, b) {
    return a - b;
}

/**
 * Multiplies a by b.
 *
 * @param {number} a - The first number.
 * @param {number} b - The second number.
 * @returns {number} The product of a and b.
 */
function multiplyNumbers(a, b) {
    return a * b;
}

/**
 * Divides a by b.
 *
 * @param {number} a - The dividend.
 * @param {number} b - The divisor.
 * @returns {number} The quotient of a and b.
 * @throws {Error} If b is zero.
 */
function divideNumbers(a, b) {
    if (b === 0) {
        throw new Error('Cannot divide by zero.');
    }
    return a / b;
}

// Validate inputs
function validateInputs(a, b) {
    if (typeof a!== 'number' || typeof b!== 'number') {
        console.error('Both inputs must be numbers.');
        return false;
    }
    return true;
}

// Main function
function calculator(a, b) {
    if (!validateInputs(a, b)) {
        return;
    }

    console.log(`Adding ${a} and ${b}: ${addNumbers(a, b)}`);
    console.log(`Subtracting ${b} from ${a}: ${subtractNumbers(a, b)}`);
    console.log(`Multiplying ${a} by ${b}: ${multiplyNumbers(a, b)}`);
    console.log(`Dividing ${a} by ${b}: ${divideNumbers(a, b)}`);
}

// Example usage
calculator(10, 2);

### Variable Definition

* `process`: The `process` object is a global object in Node.js that provides information about and control over the current process.
* `require`: The `require` function is used to import modules into the current scope.
* `module`: The `module` object is a constructor function that represents the current module.
* `exports`: The `exports` object is a property of the `module` object that allows modules to export functions, variables, or other values.