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
Contributors
Preface
Index

Extending Chart.js


There are several ways to extend Chart.js. You may use the prototype methods, callbacks, and event handlers and interact with the rendering process; you can create plugins, which have their own life cycle and are easier to reuse in other charts; and you can extend Chart.js from existing charts or even create new charts and scales.

Prototype methods

Prototype methods are automatically called during rendering and updates. You can also call them directly if you need to interfere with the rendering process. They are listed in the following table:

Method

Description

destroy()

Destroys a chart instance. This can be used if you wish to reuse the canvas, or remove the chart completely.

reset()

Restores the chart to its initial state (after layout and before its initial animation). A new animation can be triggered with render() or update().

stop()

Stops an animation loop. This is usually called in an onProgress callback. Calling render() or update() will resume the animation.

clear()

Clears...