Simple ChartJS

Simple Ruby wrapper for using ChartJS

Includes - 2.7.2

Add this line to your application's Gemfile:

gem 'simple_chartjs'

In application.js, add:

Choose the appropriate ChartJS file depending on if you want it bundled with MomentJS:

• Without Moment.js:

  //= require Chart

• With Moment.js:

  //= require Chart.bundle

Then require the simple_chartjs file

//= require simple_chartjs

And then execute:

$ bundle

Or install it yourself as:

$ gem install simple_chartjs

For faster load times simple chartjs expects you to have controllers and routes for the data to be loaded from

class ChartsController < ApplicationController
  def show
    render json: chart_data.to_json
  end

  private

  def chart_data
    {
      datasets: [{ data: [...] }],
      labels: [...]
    }
  end
end

At its simplest a chart can be produced by the following

<%= line_chart           chart_path %>
<%= bar_chart            chart_path %>
<%= horizontal_bar_chart chart_path %>
<%= radar_chart          chart_path %>
<%= polar_area_chart     chart_path %>
<%= pie_chart            chart_path %>
<%= doughnut_chart       chart_path %>
<%= bubble_chart         chart_path %>
<%= scatter_chart        chart_path %>

id, class, width, height, data are passed directly to the chart

line_chart chart_data_path, id: 'test-id', class: 'test-class', width: '100%', height: '500px', data: { options: 'test-options' }

Width and Heigth can be given either as a percentage or as pixels.

Simple ChartJS follows the same patterns as ChartJS. There is dataset properties for configuring options on the data and also options for the chart itself.

There are three ways in which the dataset properties can be set.

The dataset properties can be set in the controller like below.

def data
  {
    labels: [...],
    datasets: [
      {
        label: "My First dataset",
        data: [...],
        border_width: 4  # <-- (any of the properties listed as dataset properties in chartjs can be added to the hash)
      }
    ]
  }
end

The dataset properties can be set in the view like below.

bar_chart chart_data_path, dataset_properties: { border_width: 4 }

If you want more control from a javascript perspective you can set a function that the chart will call and add those dataset properties. To do this you name a method as a data attribute call options like below.

bar_chart chart_data_path, data: { options: 'my-chart' }

In the javascript you create a function on SimpleChart

SimpleChart.prototype.myChartOptions = function() {
  return {
    datasetProperties: {
      borderWidth: 4
    },
    options: {...}
  }
}

If you need to dynamically set a value such as Background Color for each value in the dataset, datasetProperties does support callbacks as shown below. The function will receive one argument, which is the current dataset.

SimpleChart.prototype.myChartOptions = function() {
  return {
    datasetProperties: {
      backgroundColor: function(data) {
        ...
      }
    },
    options: {...}
  }
}

There are two ways in which the Configuration options can be set.

The configuration options can be set in the view like below.

bar_chart chart_data_path, options: { scales: { x_axes: [{ bar_percentage: 0.2}] } }

If you want more control from a javascript perspective you can set a function that the chart will call and add those configuration options. To do this you name a method as a data attribute call options like below.

bar_chart chart_data_path, data: { options: 'my-chart' }

In the javascript you create a function on SimpleChart

SimpleChart.prototype.myChartOptions = function() {
  return {
    datasetProperties: {...},
    options: {
      scales: {
        xAxes: [{ barPercentage: 0.2 }]
      }
    }
  }
}

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/hvenables/simple_chartjs. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.