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JavaScript and JSON Essentials
JavaScript and JSON Essentials

JavaScript and JSON Essentials: Build light weight, scalable, and faster web applications with the power of JSON , Second Edition

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Profile Icon Sai S Sriparasa Profile Icon Joseph D'mello
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€18.99 per month
Full star icon Full star icon Full star icon Full star icon Half star icon 4.5 (2 Ratings)
Paperback Apr 2018 226 pages 2nd Edition
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Arrow left icon
Profile Icon Sai S Sriparasa Profile Icon Joseph D'mello
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€18.99 per month
Full star icon Full star icon Full star icon Full star icon Half star icon 4.5 (2 Ratings)
Paperback Apr 2018 226 pages 2nd Edition
eBook
€13.98 €19.99
Paperback
€24.99
Subscription
Free Trial
Renews at €18.99p/m
eBook
€13.98 €19.99
Paperback
€24.99
Subscription
Free Trial
Renews at €18.99p/m

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JavaScript and JSON Essentials

The JSON Structures

In Chapter 1, Getting Started with JSON, you were introduced to basic JSON, how JSON objects can be embedded into an HTML file, and how basic operations such as accessing keys can be performed on simple JSON objects. Now it's time to move ahead with some simple yet advanced steps. In this chapter, you will learn about:

  • Inserting external JavaScript
  • Accessing multilevel JSON objects
  • Performing modifications in JSON data

Now let's take a step forward and work with JSON objects that are bigger, more complex, and closer to the JSON that we would work with in real-world situations.

Inserting external JavaScript

In real-world applications, JSON can be retrieved either as a response from an asynchronous request or from a JSON feed. A website uses HTML, CSS, and JavaScript to provide a visually beautiful user interface. But there are cases where data vendors are only focused on getting data. A data feed serves their purpose; a feed is a crude way of supplying data so that others can reuse it to display the data on their websites or to ingest the data and run their algorithms on it. Such data feeds are big and cannot be directly embedded into the script tag. Let us look at how external JavaScript files can be included in an HTML file.

The following screenshot depicts the code for the external-js.html file:

<!DOCTYPE html>
<html>
<head>
<title>Include external javascript</title>
<script type="text/javascript" src=&quot...

Accessing objects in JSON

Now that we understand how to make a script call to fetch an external JavaScript file, let us use the same technique to import a JSON feed. I have generated a test employee JSON data feed with 100 records. To traverse through any JSON feed, it is important to make a note of how the data is arranged. The keys in this data feed are basic employee information such as employee number, date of birth, first name, last name, gender, hire date, titles that they have held, and the dates during which they have held those titles. A few employees have held the same title throughout their tenure, while there are some employees who have held more than one title.

This JSON file will be part of the code files for exercises.

Consider the following JSON store that we need to use to perform the operations:

let data_json = [
{
"emp_no" : "10001",
...

Performing complex operations

To tackle an array of objects, we have to handle them in an iterative method. We will have to come up with an iterative solution in which we target one object at a time; once the object is accessed, we will not target that object again. This allows us to maintain data integrity as we can avoid accessing the same object multiple times, thereby avoiding any redundancies. The looping statements in JavaScript are the while loop and the for loop. Let us take a quick look at how we can use these looping techniques to traverse through our employee's array:

<!DOCTYPE html>
<html>
<head>
<title>Test Javascript</title>
<script type="text/javascript" src="data.js"></script>
<script type="text/javascript">
console.log(data_json);
const employeeCount = data_json...

Modifying JSON

JSON retrieved from a JSON feed is always going to be read-only; as such, data feeds do not provide functionality to modify their data from unverified sources. There are many cases where we would want to ingest the data from an external data feed, and then modify that content as per our requirements. An example is a company that is using a data feed that is being supplied by a data vendor, but the data that is being provided is a lot more than the company requires. In such cases, rather than using the whole feed, the company would only extract a part of it, perform certain operations to modify it as per their requirements, and reuse the new JSON object. Let us take our employee JSON feed.

Assume that the name of the company was different during different periods. We want to group the employees by company name, which is based on when they joined. Employees who...

Summary

This chapter addressed the core concepts of how to handle static JSON feeds. We began by importing an external JSON object into our HTML file, and looped through the complex array of objects to parse and extract the required data. We used the while and for loops to loop through the array and used conditions to target our search. We completed this chapter by locally modifying the existing JSON feed and adding a new property, the employee object. Now that we have mastered accessing JSON from a static file, it is time for us to make some asynchronous calls to fetch some active JSON over HTTP.

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Key benefits

  • Use JSON with trending technologies like Angular, Hapi.js, MongoDB, Kafka, and Socket.io
  • Debug, validate, and format JSON using developer toolkits, JSONLint, and JSON Editor Online
  • Explore other JSON formats like GeoJSON, JSON-LD, BSON, and MessagePack

Description

JSON is an established and standard format used to exchange data. This book shows how JSON plays different roles in full web development through examples. By the end of this book, you'll have a new perspective on providing solutions for your applications and handling their complexities. After establishing a strong basic foundation with JSON, you'll learn to build frontend apps by creating a carousel. Next, you'll learn to implement JSON with Angular 5, Node.js, template embedding, and composer.json in PHP. This book will also help you implement Hapi.js (known for its JSON-configurable architecture) for server-side scripting. You'll learn to implement JSON for real-time apps using Kafka, as well as how to implement JSON for a task runner, and for MongoDB BSON storage. The book ends with some case studies on JSON formats to help you sharpen your creativity by exploring futuristic JSON implementations. By the end of the book, you'll be up and running with all the essential features of JSON and JavaScript and able to build fast, scalable, and efficient web applications.

Who is this book for?

If you’re a web developer with a basic understanding of JavaScript and want to write JSON data, integrate it with RESTful APIs to create faster and scalable applications, this book is for you.

What you will learn

  • Use JSON to store metadata for dependency managers, package managers, configuration managers, and metadata stores
  • Handle asynchronous behavior in applications using callbacks, promises, generators, and async-await functions
  • Use JSON for Angular 5, Node.js, Gulp.js, and Hapi.js
  • Implement JSON as BSON in MongoDB
  • Make use of JSON in developing automation scripts
  • Implement JSON for realtime using socket.io and distributed systems using Kafka

Product Details

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Publication date, Length, Edition, Language, ISBN-13
Publication date : Apr 23, 2018
Length: 226 pages
Edition : 2nd
Language : English
ISBN-13 : 9781788624701
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Product Details

Publication date : Apr 23, 2018
Length: 226 pages
Edition : 2nd
Language : English
ISBN-13 : 9781788624701
Languages :
Tools :

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Table of Contents

13 Chapters
Getting Started with JSON Chevron down icon Chevron up icon
The JSON Structures Chevron down icon Chevron up icon
AJAX Requests with JSON Chevron down icon Chevron up icon
Cross-Domain Asynchronous Requests Chevron down icon Chevron up icon
Debugging JSON 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
Introduction to hapi.js Chevron down icon Chevron up icon
Storing JSON Documents in MongoDB Chevron down icon Chevron up icon
Configuring the Task Runner Using JSON Chevron down icon Chevron up icon
JSON for Real-Time and Distributed Data Chevron down icon Chevron up icon
Case Studies in JSON Chevron down icon Chevron up icon
Other Books You May Enjoy Chevron down icon Chevron up icon

Customer reviews

Rating distribution
Full star icon Full star icon Full star icon Full star icon Half star icon 4.5
(2 Ratings)
5 star 50%
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1 star 0%
松岡孝明 Mar 22, 2023
Full star icon Full star icon Full star icon Full star icon Full star icon 5
取り扱っている店の対応がとても親切でした。
Amazon Verified review Amazon
Darwin Alphons Jose Jul 12, 2021
Full star icon Full star icon Full star icon Full star icon Empty star icon 4
Well explained and written in a simple language, easy to learn and understand.
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