Chartkick

Create beautiful JavaScript charts with one line of Ruby. No more fighting with charting libraries!

See it in action

Chartkick 4.0 was recently released - see how to upgrade

:fire: For admin charts and dashboards, check out Blazer, and for advanced visualizations, check out Vega

:two_hearts: A perfect companion to Groupdate, Hightop, and ActiveMedian

Quick Start

Add this line to your application’s Gemfile:

ruby gem "chartkick"

For Rails 6 / Webpacker, run:

sh yarn add chartkick chart.js

And in app/javascript/packs/application.js, add:

js import "chartkick/chart.js"

For Rails 5 / Sprockets, in app/assets/javascripts/application.js, add:

js //= require chartkick //= require Chart.bundle

This sets up Chartkick with Chart.js. For other charting libraries, see detailed instructions.

Charts

Line chart

erb <%= line_chart User.group_by_day(:created_at).count %>

Pie chart

erb <%= pie_chart Goal.group(:name).count %>

Column chart

erb <%= column_chart Task.group_by_hour_of_day(:created_at, format: "%l %P").count %>

Bar chart

erb <%= bar_chart Shirt.group(:size).sum(:price) %>

Area chart

erb <%= area_chart Visit.group_by_minute(:created_at).maximum(:load_time) %>

Scatter chart

erb <%= scatter_chart City.pluck(:size, :population) %>

Geo chart - Google Charts

erb <%= geo_chart Medal.group(:country).count %>

Timeline - Google Charts

erb <%= timeline [ ["Washington", "1789-04-29", "1797-03-03"], ["Adams", "1797-03-03", "1801-03-03"], ["Jefferson", "1801-03-03", "1809-03-03"] ] %>

Multiple series

erb <%= line_chart @goals.map { |goal| {name: goal.name, data: goal.feats.group_by_week(:created_at).count} } %>

or

erb <%= line_chart Feat.group(:goal_id).group_by_week(:created_at).count %>

Say Goodbye To Timeouts

Make your pages load super fast and stop worrying about timeouts. Give each chart its own endpoint.

erb <%= line_chart completed_tasks_charts_path %>

And in your controller, pass the data as JSON.

ruby class ChartsController < ApplicationController def completed_tasks render json: Task.group_by_day(:completed_at).count end end

For multiple series, add chart_json at the end.

ruby render json: Task.group(:goal_id).group_by_day(:completed_at).count.chart_json

Options

Id, width, and height

erb <%= line_chart data, id: "users-chart", width: "800px", height: "500px" %>

Min and max values

erb <%= line_chart data, min: 1000, max: 5000 %>

min defaults to 0 for charts with non-negative values. Use nil to let the charting library decide.

Min and max for x-axis - Chart.js

erb <%= line_chart data, xmin: "2021-01-01", xmax: "2022-01-01" %>

Colors

erb <%= line_chart data, colors: ["#b00", "#666"] %>

Stacked columns or bars

erb <%= column_chart data, stacked: true %>

Discrete axis

erb <%= line_chart data, discrete: true %>

Label (for single series)

erb <%= line_chart data, label: "Value" %>

Axis titles

erb <%= line_chart data, xtitle: "Time", ytitle: "Population" %>

Straight lines between points instead of a curve

erb <%= line_chart data, curve: false %>

Hide points

erb <%= line_chart data, points: false %>

Show or hide legend

erb <%= line_chart data, legend: false %>

Specify legend position

erb <%= line_chart data, legend: "bottom" %>

Donut chart

erb <%= pie_chart data, donut: true %>

Prefix, useful for currency - Chart.js, Highcharts

erb <%= line_chart data, prefix: "$" %>

Suffix, useful for percentages - Chart.js, Highcharts

erb <%= line_chart data, suffix: "%" %>

Set a thousands separator - Chart.js, Highcharts

erb <%= line_chart data, thousands: "," %>

Set a decimal separator - Chart.js, Highcharts

erb <%= line_chart data, decimal: "," %>

Set significant digits - Chart.js, Highcharts

erb <%= line_chart data, precision: 3 %>

Set rounding - Chart.js, Highcharts

erb <%= line_chart data, round: 2 %>

Show insignificant zeros, useful for currency - Chart.js, Highcharts

erb <%= line_chart data, round: 2, zeros: true %>

Friendly byte sizes - Chart.js

erb <%= line_chart data, bytes: true %>

Specify the message when data is loading

erb <%= line_chart data, loading: "Loading..." %>

Specify the message when data is empty

erb <%= line_chart data, empty: "No data" %>

Refresh data from a remote source every n seconds

erb <%= line_chart url, refresh: 60 %>

You can pass options directly to the charting library with:

erb <%= line_chart data, library: {backgroundColor: "#eee"} %>

See the documentation for Chart.js, Google Charts, and Highcharts for more info.

To customize datasets in Chart.js, use:

erb <%= line_chart data, dataset: {borderWidth: 10} %>

You can pass this option to individual series as well.

Global Options

To set options for all of your charts, create an initializer config/initializers/chartkick.rb with:

ruby Chartkick.options = { height: "400px", colors: ["#b00", "#666"] }

Customize the html

ruby Chartkick.options[:html] = '<div id="%{id}" style="height: %{height};">%{loading}</div>'

You capture the JavaScript in a content block with:

ruby Chartkick.options[:content_for] = :charts_js

Then, in your layout, use:

erb <%= yield :charts_js %>

For Padrino, use yield_content instead of yield.

This is great for including all of your JavaScript at the bottom of the page.

Data

Pass data as a hash or array

erb <%= pie_chart({"Football" => 10, "Basketball" => 5}) %> <%= pie_chart [["Football", 10], ["Basketball", 5]] %>

For multiple series, use the format

erb <%= line_chart [ {name: "Series A", data: series_a}, {name: "Series B", data: series_b} ] %>

Times can be a time or a string (strings are parsed)

erb <%= line_chart({20.day.ago => 5, "2021-05-07 00:00:00 UTC" => 7}) %>

Multiple Series

You can pass a few options with a series:

• name
• data
• color
• dataset - Chart.js only
• points - Chart.js only
• curve - Chart.js only

Code

If you want to use the charting library directly, get the code with:

erb <%= line_chart data, code: true %>

The code will be logged to the JavaScript console. JavaScript functions cannot be logged, so it may not be identical.

Download Charts

Chart.js only

Give users the ability to download charts. It all happens in the browser - no server-side code needed.

erb <%= line_chart data, download: true %>

Safari will open the image in a new window instead of downloading.

Set the filename

erb <%= line_chart data, download: {filename: "boom"} %>

Set the background color

erb <%= line_chart data, download: {background: "#ffffff"} %>

Set title

erb <%= line_chart data, title: "Awesome chart" %>

Installation

Add this line to your application’s Gemfile:

ruby gem "chartkick"

Next, choose your charting library.

• Chart.js
• Google Charts
• Highcharts

Chart.js

For Rails 6 / Webpacker, run:

sh yarn add chartkick chart.js

And in app/javascript/packs/application.js, add:

js import "chartkick/chart.js"

For Rails 5 / Sprockets, in app/assets/javascripts/application.js, add:

js //= require chartkick //= require Chart.bundle

Google Charts

In your layout or views, add:

erb <%= javascript_include_tag "https://www.gstatic.com/charts/loader.js" %>

For Rails 6 / Webpacker, run:

sh yarn add chartkick

And in app/javascript/packs/application.js, add:

js import "chartkick"

For Rails 5 / Sprockets, in app/assets/javascripts/application.js, add:

js //= require chartkick

To specify a language or Google Maps API key, use:

js Chartkick.configure({language: "de", mapsApiKey: "..."})

before your charts.

Highcharts

For Rails 6 / Webpacker, run:

sh yarn add chartkick highcharts

And in app/javascript/packs/application.js, add:

js import "chartkick/highcharts"

For Rails 5 / Sprockets, download highcharts.js into vendor/assets/javascripts (or use yarn add highcharts in Rails 5.1+), and in app/assets/javascripts/application.js, add:

js //= require chartkick //= require highcharts

Sinatra and Padrino

Download chartkick.js and include it manually.

html <script src="chartkick.js"></script>

Then include the charting library.

Chart.js - download Chart.js and the date-fns adapter bundle

html <script src="chart.js"></script> <script src="chartjs-adapter-date-fns.bundle.js"></script>

Google Charts

html <script src="https://www.gstatic.com/charts/loader.js"></script>

Highcharts - download highcharts.js

html <script src="highcharts.js"></script>

Multiple Libraries

If more than one charting library is loaded, choose between them with:

erb <%= line_chart data, adapter: "google" %> <!-- or highcharts or chartjs -->

JavaScript API

Access a chart with:

javascript var chart = Chartkick.charts["chart-id"]

Get the underlying chart object with:

javascript chart.getChartObject()

You can also use:

javascript chart.getElement() chart.getData() chart.getOptions() chart.getAdapter()

Update the data with:

javascript chart.updateData(newData)

You can also specify new options:

javascript chart.setOptions(newOptions) // or chart.updateData(newData, newOptions)

Refresh the data from a remote source:

javascript chart.refreshData()

Redraw the chart with:

javascript chart.redraw()

Destroy the chart with:

javascript chart.destroy()

Loop over charts with:

javascript Chartkick.eachChart( function(chart) { // do something })

Content Security Policy (CSP)

Check out how to configure CSP

No Ruby? No Problem

Check out chartkick.js

Tutorials

• Charts with Chartkick and Groupdate
• Creando gráficos en Ruby on Rails con Chartkick y Chart.js
• Make Easy Graphs and Charts on Rails with Chartkick
• Practical Graphs on Rails: Chartkick in Practice

Upgrading

4.0

If you use Sprockets, update the gem and you’re good to go!

If you use Webpacker, run:

sh yarn upgrade chartkick --latest

If you use Chart.js with Webpacker, also run:

sh yarn upgrade chart.js --latest

And in app/javascript/packs/application.js, change:

js require("chartkick") require("chart.js")

to:

js require("chartkick/chart.js")

History

View the changelog

Contributing

Everyone is encouraged to help improve this project. Here are a few ways you can help:

• Report bugs
• Fix bugs and submit pull requests
• Write, clarify, or fix documentation
• Suggest or add new features

To get started with development:

sh git clone https://github.com/ankane/chartkick.git cd chartkick bundle install bundle exec rake test