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

Cartesian axes, ticks, and grid lines

There are five chart types that use Cartesian grids: bar, horizontalBar, line, scatter, and bubble. Every chart has two scales, one for each perpendicular axis. Each scale can be of four types:

  • type:'linear': A numeric scale that can be used to compare values of the same order of magnitude.
  • type:'logarithmic': A numeric scale to compare values that differ in order of magnitude.
  • type:'category': A list of unordered categories.
  • type:'time': An ordered list of instants. This scale requires the moment.js library.

In most charts, at least one of the scales is numeric (linear or logarithmic). In scatterplots and bubble charts, both scales are numeric. Time-series charts use a numeric scale and a time scale, but you can also use a category scale. You can also create correlation charts where both scales are categories.

The following table lists common configuration options for all Cartesian axes (the three last are objects, which contain specific configuration parameters...