Book Image

Learn Chart.js

By : Helder da Rocha
Book Image

Learn Chart.js

By: Helder da Rocha

Overview of this book

Chart.js is a free, open-source data visualization library, maintained by an active community of developers in GitHub, where it rates as the second most popular data visualization library. If you want to quickly create responsive Web-based data visualizations for the Web, Chart.js is a great choice. This book guides the reader through dozens of practical examples, complete with code you can run and modify as you wish. It is a practical hands-on introduction to Chart.js. If you have basic knowledge of HTML, CSS and JavaScript you can learn to create beautiful interactive Web Canvas-based visualizations for your data using Chart.js. This book will help you set up Chart.js in a Web page and show how to create each one of the eight Chart.js chart types. You will also learn how to configure most properties that override Chart’s default styles and behaviors. Practical applications of Chart.js are exemplified using real data files obtained from public data portals. You will learn how to load, parse, filter and select the data you wish to display from those files. You will also learn how to create visualizations that reveal patterns in the data. This book is based on Chart.js version 2.7.3 and ES2015 JavaScript. By the end of the book, you will be able to create beautiful, efficient and interactive data visualizations for the Web using Chart.js.
Table of Contents (14 chapters)
Title Page
Copyright and Credits
About Packt

Chapter 1. Introduction

This is a book about data visualization using JavaScript with Chart.js, one of the most popular data visualization libraries, and also one of the easiest to use. Chart.js provides ready-to-use interactive visualizations for your data with minimal coding. After loading your data into a standard JavaScript array, you can add styles and other configuration using simple object-based declarative structures. Chart.js automatically scales your data, generates ticks and grid lines, creates interactive tooltips, and fits the available space, making your chart automatically responsive. It's a great way to start creating data visualizations for the Web.

Chart.js is free, open source, and maintained by an active community of developers on GitHub. As a data visualization library, it is in second place on GitHub in terms of the number of stars it has. First place belongs to D3.js, a much larger and complex library with a steep learning curve. You still need to know JavaScript, HTML, and CSS to use Chart.js, but you don't have to be a guru. Besides JavaScript, it's also based on other Web standards, such as DOM, CSS, and Canvas. Charts are automatically rendered in Canvas and control all canvas configuration, resizing, and pixel ratios. The only thing you need to know about Canvas is how to include a <canvas> tag in your page and obtain a context, but Canvas knowledge can be useful in advanced charts.

This book assumes you know some JavaScript, HTML, and CSS. The next chapter provides a quick refresher on specific topics and the main technologies you are likely to encounter while learning Chart.js. You can skip it and jump straight to Chapter 3Chart.js – Quick Start, if you wish. This chapter provides a brief introduction to data visualization and data visualization frameworks, and gives an overview of the rest of the book.

This chapter will cover the following topics:

  • Data visualization
  • Why use a data visualization library?
  • How to use this book