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

Default configuration

Every chart created in Chart.js comes previously configured with default properties. You can always override these properties in the options object when creating a new Chart instance, but you can also override them for all or for many of your charts, by setting the properties directly in the Chart.defaults object.


For example, the default line tension is 0.4 for any kind of chart. If you want all your charts to use only straight lines and have scales beginning at zero, you can make all pages load a defaults.js file that declares the following defaults: = 0;
Charts.defaults.scales.ticks.beginAtZero = true;

If you want to have only curved lines in the radar charts, you can override the property for all radar charts (but not any other kind of chart) using the following:

Charts.defaults.radar.elements.line.tension = 0.4;

Then, if you have a specific line chart where you would prefer to use curved lines, you can again override the...