JavaScript: Functional Programming for JavaScript Developers

The application – an e-commerce website

In pursuit of a real-world application, let's say we need an e-commerce web application for a mail-order coffee bean company. They sell several types of coffee and in different quantities, both of which affect the price.

Imperative methods

First, let's go with the procedural route. To keep this demonstration down to earth, we'll have to create objects that hold the data. This allows the ability to fetch the values from a database if we need to. But for now, we'll assume they're statically defined:

// create some objects to store the data. var columbian = { name: 'columbian', basePrice: 5 }; var frenchRoast = { name: 'french roast', basePrice: 8 }; var decaf = { name: 'decaf', basePrice: 6 }; // we'll use a ...