wine.js

 function winePrice(rating, age){
	var peak_age = rating - 50,
		price

	price = rating / 2

	if (age > peak_age){
		// past it's peak, goes bad in 5 years
		price = price * (5 - (age - peak_age) )
	}// if
	else{
		// increases to 5x original value as it 
		// approaches it's peak
		price = price * (5 * ( (age + 1) / peak_age))

	}// else

	if (price < 0 ){
		price = 0
	}// if
	return price
}

function generateWineDataset(num_of_elements){
	var rows = [],
		price,
		age,
		rating,
		i

	for(i = 0; i < num_of_elements; i++){

		// creating a random age and rating
		rating = Math.random() * 50 + 50
		age    = Math.random() * 50
		
		// get reference price
		price  = winePrice(rating, age)
		
		// add some noise
		price  = price * (Math.random() * 0.4 + 0.8)

		// add to dataset
		rows.push({rating: rating, age: age, price: price})
	}// for
	return rows
}
// Heterogeneous variables
// adding additional variables
function generateWineDataset2(num_of_elements){
	var rows = [],
		price, // price of the wine
		age, // age of the wine
		rating, // wine rating
		aisle, // aisle no of a bottle  - where it's located
		bottle_sizes = [375.0, 750.0, 1500.0, 3000.0],
		bottle_size, // size of the bottle
		i

	for(i = 0; i < num_of_elements; i++){

		// creating a random age and rating
		rating      = Math.random() * 50 + 50
		age         = Math.random() * 50
		aisle       = Math.floor(Math.random() * (20 - 1 + 1)) + 1 // 1..20
		bottle_size = bottle_sizes[Math.floor(Math.random() * ( bottle_sizes.length -1 - 0 + 1)) + 0]
		// get reference price
		price       = winePrice(rating, age)
		price      *= (bottle_size / 750)
		
		// add some noise
		price       = price * (Math.random() * 0.9 + 0.2)

		// add to dataset
		rows.push({rating: rating, age: age, price: price, aisle: aisle, bottle_size: bottle_size})
	}// for
	return rows
}

module.exports = {

					winePrice: winePrice,
					generateWineDataset: generateWineDataset,
					generateWineDataset2: generateWineDataset2
				}