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)

Datatypes in JSON


Now, let us take a look at a more complex example of JSON. We'll also go over all the datatypes that are supported by JSON. JSON supports six datatypes: strings, numbers, Booleans, arrays, objects, and null.

In the preceding example, we have five key-value pairs of different datatypes. Now let us take a close look at each of these key-value pairs:

The datatype of the value that "id" references is a number.

Here, the datatype of the value that "name" references is a string.

In the preceding screenshot, the datatype of the value that "isStudent" references is a Boolean.

The datatype of the value that "scores" references here is an array.

Here the datatype of the value that "courses" references is an object.

We know that JSON supports six datatypes; they are strings, numbers, Booleans, arrays, objects, and null. Yes, JSON supports null data, and real-time business implementations need accurate information. There might be cases where null was substituted with an empty string, but...