Node.js By Example

Defining and using modules

JavaScript as a language does not have mechanisms to define real classes. In fact, everything in JavaScript is an object. We normally inherit properties and functions from one object to another. Thankfully, Node.js adopts the concepts defined by CommonJS—a project that specifies an ecosystem for JavaScript.

We encapsulate logic in modules. Every module is defined in its own file. Let's illustrate how everything works with a simple example. Let's say that we have a module that represents this book and we save it in a file called book.js:

// book.js
exports.name = 'Node.js by example';
exports.read = function() {
   console.log('I am reading ' + exports.name);
}

We defined a public property and a public function. Now, we will ...