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JavaScript and JSON Essentials
JavaScript and JSON Essentials

JavaScript and JSON Essentials: If you fancy a less verbose data format than CSV or XML, then JSON could be for you. This tutorial will teach you about using JSON with JavaScript for effective local storage or Internet transfers.

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JavaScript and JSON Essentials

Chapter 2. Getting Started with JSON

JSON or JavaScript Object Notation is a very popular data interchange format. It was developed by Douglas Crockford. JSON is text-based, lightweight, and a human-readable format for data exchange between clients and servers. JSON is derived from JavaScript and bears a close resemblance to JavaScript objects, but it is not dependent on JavaScript. JSON is language-independent, and support for the JSON data format is available in all the popular languages, some of which are C#, PHP, Java, C++, Python, and Ruby.

Note

JSON is a format and not a language.

JSON can be used in web applications for data transfer. Prior to JSON, XML was considered to be the chosen data interchange format. XML parsing required an XML DOM implementation on the client side that would ingest the XML response, and then XPath was used to query the response in order to access and retrieve the data. That made life tedious, as querying for data had to be performed at two levels: first on...

The Hello World program with JSON


Now that we have a basic understanding of JSON, let us work on our Hello World program. This is shown in the screenshot that follows:

The preceding program will alert World onto the screen when it is invoked from a browser. Let us pay close attention to the script between the <script> tags.

In the first step, we are creating a JavaScript variable and initializing the variable with a JavaScript object. Similar to how we retrieve data from a JavaScript object, we use the key-value pair to retrieve the value. Simply put, JSON is a collection of key and value pairs, where every key is a reference to the memory location where the value is stored on the computer. Now let us take a step back and analyze why we need JSON, if all we are doing is assigning JavaScript objects that are readily available. The answer is, JSON is a different format altogether, unlike JavaScript, which is a language.

Note

JSON keys and values have to be enclosed in double quotes, if either...

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...

Languages that support JSON


Until now, we have seen how the parsers in JavaScript support JSON. There are many other programming languages that provide implementations for JSON. Languages such as PHP, Python, C#, C++, and Java provide a very good support for the JSON data interchange format. All of the popular programming languages that support service-oriented architecture have understood the importance of JSON and its implementation for data transfer, thus, they have provided great support for JSON. Let us take a quick detour from implementing JSON in JavaScript, and see how JSON is implemented in other languages, such as PHP and Python.

PHP

PHP is considered to be one of the most popular languages for building web applications. It is a server-side scripting language that allows developers to build applications that can perform operations on the server, connect to a database to perform CRUD (Create, Read, Update, Delete) operations, and provide a stately environment for real-time applications...

Summary


This chapter introduced us to the basics of JSON. We went through the history of JSON, and understood its advantages over XML. We created our first JSON object and successfully parsed it. Also, we went over all the datatypes that JSON supports. Finally, we went over some examples as to how JSON can be implemented in other programming languages. As we move forward in this journey, we will find the knowledge that we have gathered in this chapter to be a solid foundation for the more complex concepts that we will go over in the later chapters.

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Key benefits

  • Deploy JSON across various domains
  • Facilitate metadata storage with JSON
  • Build a practical data-driven web application with JSON

Description

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.

Who is this book for?

This book is a great resource for developers who would like to learn more about JSON and who wish to apply it in their own projects. It will be useful to have some prior knowledge of HTML and JavaScript to help you understand the concepts covered in this book. Some familiarity with a server-side language such as PHP, C#, or Python would also be beneficial, but this is not compulsory.

What you will learn

  • Learn how to work with real-time JSON
  • Transfer JSON data via asynchronous calls
  • Fire cross-domain asynchronous requests
  • Serialize and transmit data
  • Build the Carousel application
  • Understand alternate implementations of JSON
  • Debug JSON quickly and efficiently

Product Details

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Publication date : Oct 24, 2013
Length: 120 pages
Edition : 1st
Language : English
ISBN-13 : 9781783286041
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Product Details

Publication date : Oct 24, 2013
Length: 120 pages
Edition : 1st
Language : English
ISBN-13 : 9781783286041
Languages :

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Table of Contents

8 Chapters
JavaScript Basics Chevron down icon Chevron up icon
Getting Started with JSON Chevron down icon Chevron up icon
Working with Real-time JSON Chevron down icon Chevron up icon
AJAX Calls with JSON Data Chevron down icon Chevron up icon
Cross-domain Asynchronous Requests Chevron down icon Chevron up icon
Building the Carousel Application Chevron down icon Chevron up icon
Alternate Implementations of JSON Chevron down icon Chevron up icon
Debugging JSON Chevron down icon Chevron up icon

Customer reviews

Top Reviews
Rating distribution
Full star icon Full star icon Full star icon Half star icon Empty star icon 3.1
(15 Ratings)
5 star 6.7%
4 star 40%
3 star 26.7%
2 star 13.3%
1 star 13.3%
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Top Reviews

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Roark Dec 25, 2013
Full star icon Full star icon Full star icon Full star icon Full star icon 5
This book got me up to speed with the in's and out's of JSON in one afternoon. With it, I was able to bring my Web skills up to date.
Amazon Verified review Amazon
Richard Crespo Silverio Oct 19, 2017
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
Very good book for a developer to understand and learn JSON. Very good example provided on each chapter. There ware a few examples though that took time to get to work, hence the reason for 4 stars. I would recommend this to any developer who wants to get started or familiarize himself/ herself with JSON.
Amazon Verified review Amazon
CS Jan 03, 2014
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
Knappe und prägnant gehaltene Einführung ins Thema - nicht mehr und nicht weniger. Die Beispiele bauen auf einander auf und sind gut erklärt.
Amazon Verified review Amazon
K. C. Jul 30, 2016
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
4 stars because the book is very short in terms of number of pages. It does provide only the essentials of JavaScript and JSON, as stated in the title. I would like to have seen another example with a variety of JSON supported data types used or just more examples or sample files with the html, javascript and JSON. The book did help me understand something of the use of the languages together.
Amazon Verified review Amazon
Howard Gissinger Jul 27, 2015
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
very well presented
Amazon Verified review Amazon
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