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

Options configuration

Defaults are configured per chart with an options configuration object included in the chart object (the second parameter of the constructor), as demonstrated in the following block of code:

new Chart("ocean-volume-bar-chart",
            type: "bar",
            data: dataObj,
            options: {} // configure options here

There are many defaults that you can change. You might, for example, wish to have more control over the size of your chart, which resizes automatically. That happens because charts are responsive by default. You can turn responsiveness off by overriding the responsive property, which has a default true value, as follows:

options: {
    responsive: false

Now, your chart no longer resizes automatically. However, what if you do want to undertake resizing, but don't care about the aspect ratio? Then, you can override the maintainAspectRatio property, as follows:

options: {
    maintainAspectRatio: false

You might want this if your...