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

Working with larger and multiple datasets

From what we have seen so far, you should already be able to create a simple bar chart. In this section, we will explore some configuration options related to large datasets, which you will probably load as an external file, and multiple datasets, which can be plotted on the same chart.

Loading data

Many times, your data will be available online and you may want to load it dynamically. It's also a good idea to keep your data and code in separate files. If you have data in a CSV file, you can load it into your JavaScript code and use it to generate the chart.

JavaScript loads data asynchronously using Ajax. You can use standard Ajax, JQuery, or the ES6 fetch function, which functions like a JavaScript promise. After you load the CSV file, you need to parse it. If you only need one set of category labels and values, you can handle it without a parser.

In this example, we will use a CSV file that contains the amount of plastic waste disposed of in the oceans...