This component is available on GitHub.

Stimulus Chartjs

A Stimulus controller to deal with chart.js.

Installation

$ yarn add stimulus-chartjs

And use it in your JS file:

// Probably in app/javascript/controllers/index.js

import { Application } from 'stimulus'
import Chart from 'stimulus-chartjs'

const application = Application.start()
application.register('chart', Chart)

Usage

Basic usage

<canvas
  data-controller="chart"
  data-chart-data-value='{ "labels": ["January", "February", "March", "April", "May", "June", "July"], "datasets": [{ "label": "My First dataset", "backgroundColor": "transparent", "borderColor": "#3B82F6", "data": [37, 83, 78, 54, 12, 5, 99] }] }'
></canvas>

If you extend this controller, it could be handy to with it with a target:

<div
  data-controller="chart"
  data-chart-data-value='{ "labels": ["January", "February", "March", "April", "May", "June", "July"], "datasets": [{ "label": "My First dataset", "backgroundColor": "transparent", "borderColor": "#3B82F6", "data": [37, 83, 78, 54, 12, 5, 99] }] }'
>
  <canvas data-chart-target="canvas"></canvas>

  <!-- You need to define this action -->
  <button data-action="chart#update">Update me!</button>
</div>

It's much simpler with a framework.

With backend framework (optional)

In your controller:

class ChartsController < ApplicationController
  def index
    @chart_data = {
      labels: %w[January February March April May June July],
      datasets: [{
        label: 'My First dataset',
        backgroundColor: 'transparent',
        borderColor: '#3B82F6',
        data: [37, 83, 78, 54, 12, 5, 99]
      }]
    }

    @chart_options = {
      scales: {
        yAxes: [{
          ticks: {
            beginAtZero: true
          }
        }]
      }
    }
  end
end

In your view:

<canvas
  data-controller="chart"
  data-chart-data-value="<%= @chart_data.to_json %>"
  data-chart-options-value="<%= @chart_options.to_json %>"
></canvas>

🛠 Configuration

AttributeDefaultDescriptionOptional
data-chart-data-value{}The data for Chart.js❌
data-chart-type-valuelineType of the chart✅
data-chart-options-value{}The options for Chart.js✅

🎛 Extending Controller

You can use inheritance to extend the functionality of any Stimulus component:

import Chart from 'stimulus-chartjs'

export default class extends Chart {
  connect() {
    super.connect()
    console.log('Do what you want here.')

    // The chart.js instance
    this.chart

    // Options from the data attribute.
    this.options

    // Default options for every charts.
    this.defaultOptions
  }

  // Bind an action on this method
  async update() {
    const response = await fetch('https://example.com/chart_data.json')
    const data = await response.json()

    this.chart.data = data
    this.chart.update()
  }

  // You can set default options in this getter for all your charts.
  get defaultOptions() {
    return {
      maintainAspectRatio: false,
      legend: {
        display: false,
      },
    }
  }
}

This controller will automatically have access to targets defined in the parent class.

If you override the connect, disconnect or any other methods from the parent, you'll want to call super.method() to make sure the parent functionality is executed.

☕️ Sponsors

Stimulus Component is an MIT licensed open source project and completely free to use. However, the amount of effort needed to maintain and develop new features for the project is not sustainable without proper financial backing. You can support Stimulus Components development on Github Sponsors. 🙏

👷 Contributing

Do not hesitate to contribute to the project by adapting or adding features ! Bug reports or pull requests are welcome.

Don’t forget to drop a 🌟 on Github to support the project.

📝 License

This project is released under the MIT license.