In this series we're looking at comparisons of JavaScript chart libraries. JavaScript is a huge ecosystem with many frameworks, plugins and libraries allowing you to create charts & graphs in your applications. Choosing the right JavaScript chart for your application is something which requires careful consideration depending on your requirements. In these helpful guides, we will be comparing popular JavaScript Charts to help you make the right decision depending on your needs.

Today we're looking at Chart.js. We're going to discuss what is Chart.js, what are the pros & cons of Chart.js, how to improve Chart.js performance and finally alternatives to Chart.js for enterprise software applications.

What is Chart.js?

Chart.js is a free, open-source JavaScript library for data visualization, which supports eight chart types: bar, line, area, pie, bubble, radar, polar and scatter. It's licensed under the permissive MIT license and is renowned for being flexible, lightweight, easy to use and extendible.

Based on HTML5 and Canvas, Chart JS is simpler than SVG based libraries and has the ability to animate charts, incorporate tooltips or handle responsive layout easily.

What are the pros & Cons of Chart.js

Advantages of Chart.js

Here are the pros of Chart.js:

• Provides responsive, animated charts with a clean look & feel
• Lightweight core library: 199kb minified and 67kb Gzipped according to Bundlephobia
• Free open source, with a permissive MIT license
• Simple, easy to use and get started
• Good documentation & samples for an open source library
• Popular, with a large community and plenty of contributors
• Extensible, via a plugin architecture allowing for additional chart types, features or interactions to be built.

Disadvantages or Drawbacks of Chart.js

Here are the cons of ChartJS.

• Only 8 basic chart types & features available in the core library
• Additional chart types & features require plugins which may not have the same development pace or community as the main core library
• Does not support advanced chart types like heatmap
• Adding things like interactivity require plugins
• No support for 3D charts
• According to internet searches, Chart.js is slow and struggles with performance with large datasets.For example, some Github issues report:
  • Chart.js wildly slow and unusable with large numbers but small dataset
  • Chart.js unusably slow with many data-points
  • Line chart with big-data resizes very slowly
  • Zoom speed on large data
• Realtime or dynamic updates are challenging, with performance problems reported here also
• Sometimes rendering issues due to API instability or gripes with the API are reported in reviews
• Open source means lack of enterprise technical support, although as mentioned before the community is strong

How to improve Chart.js Performance?

Rendering performance often comes up as a disadvantage of Chart.js. For a simple application with no more than a few JS charts with small data this may not be a problem. However, data is getting bigger and bigger all the time. Dashboards in applications may have to deal with tens of charts, each with a number of series and thousands of data-points per series. This can add up to a huge problem as requirements become more complex.

According to the Chart.js docs on performance:

#1 Chart.js is fastest if you provide data with indices that are unique, sorted, and consistent across datasets

#2 Decimation is available as an option which reduces number of datapoints on screen. However, it comes with limitations such as dataset must be a line, sorted in X

#3 Animations may be disabled which reduces CPU usage and improves rendering time

#4 Specifying min and max for scales avoids the need to calculate the axis range from data.

What alternatives are there to Chart.js?

For applications which have demanding requirements, complex dashboards or big-data / performance requirements one viable alternative is SciChart.js' JavaScript Chart Library.

One of the differences about SciChart.js is it's designed for demanding applications that require high performance, or complex visualisations & interactions. It's particularly focussed on enterprises building mission-critical apps, citing scientific, medical users like Siemens, financial firms such as JP Morgan & aerospace such as Nasa as key customers.

SciChart.js is designed for the following types of application:

• Apps moving from Desktop to JavaScript which expect high-performance or big-data handling
• Complex interactions, zooming, panning, linking of charts, tooltips and annotations available out of the box
• SaaS apps, enterprise apps or Electron (desktop) apps
• Enterprise apps which find tech-support a value-add

With support for React, Vue, Angular, enterprise tech-support and a wide set of docs, examples and demos, SciChart.js can quickly pay back the investment in time / cost savings when building your applications.

What are the Advantages of SciChart.js vs. Chart.js?

When compared to Chart.js, SciChart.js has the following advantages:

• High performance for big datasets (1k, 10k, 100k, 1M, 10M+)
• Many chart types including 2D & 3D charts out of the box
• Allows complex chart interactions, allowing you to create rich dashboards
• Extensibility with many API endpoints
• Extensive (hundreds of pages of) documentation with embedded codepens and hundreds of demos online.
• Enterprise tech support with fast bug fix turnaround and a high release cadence, allowing you to save time & money in your projects.

Learn more about SciChart.js

To learn more about SciChart.js or to discover it's features, take a look at the following blog post:

Blog: Best JavaScript Chart Libraries 2024: Finding the Right Fit for your JS Applications

Further Reading

• What are the features of SciChart.js?
• How to get started with SciChart.js?
• Is SciChart.js free? Discovering the Community Edition.
• Who uses SciChart.js and what do they say?