Create beautiful JavaScript charts with one line of Ruby

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Quick Start

Add this line to your application's Gemfile:

gem "chartkick"

For Rails 6 / Webpacker, run:

yarn add chartkick chart.js

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

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

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

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

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

Charts

Line chart

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<%= line_chart User.group_by_day(:created_at).count %>
Install Groupdate to use the group_by_day method

Pie chart

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<%= pie_chart Yogurt.group(:flavor).count %>

Column chart

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<%= column_chart Order.group_by_day_of_week(:created_at, format: "%a").count %>

Bar chart

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

Area chart

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

Scatter chart

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<%= scatter_chart City.pluck(:size, :population), xtitle: "Size", ytitle: "Population" %>

Geo chart - Google Charts

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

Timeline - Google Charts

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

Multiple series

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

or

<%= 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.

<%= line_chart completed_tasks_charts_path %>

And in your controller, pass the data as JSON.

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.

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

Options

Id, width, and height

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

Min and max values

<%= 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

<%= line_chart data, xmin: "2018-01-01", xmax: "2019-01-01" %>

Colors

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

Stacked columns or bars

<%= column_chart data, stacked: true %>

Discrete axis

<%= line_chart data, discrete: true %>

Label (for single series)

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

Axis titles

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

Straight lines between points instead of a curve

<%= line_chart data, curve: false %>

Hide points

<%= line_chart data, points: false %>

Show or hide legend

<%= line_chart data, legend: false %>

Specify legend position

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

Defer chart creation until after the page loads

<%= line_chart data, defer: true %>

Donut chart

<%= pie_chart data, donut: true %>

Prefix, useful for currency - Chart.js, Highcharts

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

Suffix, useful for percentages - Chart.js, Highcharts

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

Set a thousands separator - Chart.js, Highcharts

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

Set a decimal separator - Chart.js, Highcharts

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

Set significant digits - Chart.js, Highcharts

<%= line_chart data, precision: 3 %>

Set rounding - Chart.js, Highcharts

<%= line_chart data, round: 2 %>

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

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

Friendly byte sizes - Chart.js 2.8+

<%= line_chart data, bytes: true %>

Show a message when data is empty

<%= line_chart data, messages: {empty: "No data"} %>

Refresh data from a remote source every n seconds

<%= line_chart url, refresh: 60 %>

You can pass options directly to the charting library with:

<%= 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:

<%= 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:

Chartkick.options = {
  height: "400px",
  colors: ["pink", "#999"]
}

Customize the html

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

You capture the JavaScript in a content block with:

Chartkick.options[:content_for] = :charts_js

Then, in your layout:

<%= yield :charts_js %> <!-- Rails -->
<%= yield_content :charts_js %> <!-- Padrino -->

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

Data

Pass data as a Hash or Array

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

For multiple series, use the format

<%= 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)

<%= line_chart({20.day.ago => 5, "2013-05-07 00:00:00 UTC" => 7}) %>

Multiple Series

You can pass a few options with a series:

Code

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

<%= line_chart data, code: true %>

The code will be logged to the JavaScript console.

Note: 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.

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<%= line_chart data, download: true %>

Set the filename

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

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

Set the background color

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

Installation

Add this line to your application's Gemfile:

gem "chartkick"

Next, choose your charting library.

In the instructions below, application.js must be included before the charts in your views, unless using the :content_for option.

Chart.js

For Rails 6 / Webpacker, run:

yarn add chartkick chart.js

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

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

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

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

Google Charts

In your layout or views, add:

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

For Rails 6 / Webpacker, run:

yarn add chartkick

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

require("chartkick")

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

//= require chartkick

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

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

before your charts.

Highcharts

For Rails 6 / Webpacker, run:

yarn add chartkick highcharts

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

require("chartkick").use(require("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:

//= require chartkick
//= require highcharts

Sinatra and Padrino

Download chartkick.js and include it manually.

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

Multiple Libraries

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

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

JavaScript API

Access a chart with:

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

Get the underlying chart object with:

chart.getChartObject()

You can also use:

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

Update the data with:

chart.updateData(newData)

You can also specify new options:

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

Refresh the data from a remote source:

chart.refreshData()

Redraw the chart with:

chart.redraw()

Loop over charts with:

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

Upgrading

3.0

Breaking changes

2.0

Breaking changes

Credits

Chartkick uses iso8601.js to parse dates and times.

History

View the changelog

Chartkick follows Semantic Versioning

Contributing

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

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