Book Image

JavaScript and JSON Essentials

By : Sai S Sriparasa
Book Image

JavaScript and JSON Essentials

By: Sai S Sriparasa

Overview of this book

The exchange of data over the Internet has been carried out since its inception. Delimiter-separated lists such as CSV and tag-separated languages such as XML are very popular, yet they are considered to be verbose by a section of developers. JSON (JavaScript Object Notation) is a lightweight text-based code to create objects to transfer data over the Internet. It is a data exchange format that is human-readable (like XML, but without the markup around your actual payload) and its syntax is a subset of the JavaScript language that was standardized in 1999. JavaScript and JSON Essentials is a step-by-step guide that will introduce you to JSON and help you understand how the lightweight JSON data format can be used in different ways either to store data locally or to transfer data over the Internet. This book will teach you how to use JSON effectively with JavaScript. This book begins with a brief refresher course on JavaScript before taking you through how JSON data can be transferred via synchronous, asynchronous, and cross-domain asynchronous HTTP calls. JSON is not just about data transfer; this book throws light on the alternate implementations of JSON as well. You will learn the data types that JavaScript uses and how those data types can be used in JSON. You will go through the concepts of how to create, update, parse, and delete a JSON object. You will also look at the different techniques of loading a JSON file onto a web page, how to use jQuery to traverse through an object, and how to perform access operations. You will also go over a few resources that will make debugging JSON quick and easy.
Table of Contents (15 chapters)

JSON for storing metadata

On the same line as dependency managers, JSON is also used to store metadata for software projects. Prior to JSON becoming popular, the configurations and metadata were either stored in a text file or in language-specific files, such as config.php for PHP, for Python, and config.js for JavaScript. All these can now be replaced by a language-independent config.json file; use a JSON library for non-JavaScript libraries to parse it. Let's take a quick look at an example config.json file:


In the config.json file, we store the metadata as a JSON object. We are specifying important information such as the project name, the environment of the project (which varies based on the server that the file is located on), any classes that have to be autoloaded during bootstrapping the application, and any classes or folders that we would want to exclude. Finally, using the RECURSIVE key, we also specify that there are folders and those folders have files.