chartjs-plugin-waterfall

Installation

npm install --save chartjs-plugin-waterfall

Here's what it looks like:

Usage

Just import the plugin and add it to any chart that you want to be a waterfall chart like so:

import waterFallPlugin from 'chartjs-plugin-waterfall';

var chart = new Chart(ctx, {
    plugins: [waterFallPlugin]
});

See the plugins documentation for more info.

How it works

This plugin works by checking if any of your datasets contain a property called dummyStack that is set to true. The stack property must be used in conjunction with dummyStack for this plugin to work properly. If dummyStack is true then it hides the label, tooltip and sets the color invisible. When you use stacking with this it creates the affect of a floating bar as shown in the image above that we can use for waterfall charts as chartjs-2 doesn't support waterfall charts by default.

E.g:

const data = {
  datasets: [
    {
      label: 'Closing Costs',
      data: [50],
      backgroundColor: '#e8cdd7',
      stack: 'stack 1',
    },
    {
      label: 'Purchase Price',
      data: [700],
      backgroundColor: '#d29baf',
      stack: 'stack 1',
    },
    {
      data: [200],
      dummyStack: true,
      stack: 'stack 2',
    },
    {
      label: 'Opening Loan Balance',
      data: [550],
      backgroundColor: '#bb6987',
      stack: 'stack 2',
    },
    {
      label: 'Initial Cash Investment',
      data: [200],
      backgroundColor: '#a53860',
      stack: 'stack 3',
    },
  ],
};

This dataset will give us the look in the image above.

Options

You specify options for this plugin on the options.plugins.waterFallPlugin key for example like this:

options: {
  plugins: {
    waterFallPlugin: {
      stepLines: {
        enabled: true,
        startColorStop: 0,
        startColor: `rgba(${0xd2}, ${0x9b}, ${0xaf}, 0.55`, // opaque
        endColorStop: 0.6,
        endColor: `rgba(${0xd2}, ${0x9b}, ${0xaf}, 0`, // transparent
      },
    },
  },
  // Your other standard chartjs options here
}

stepLines.enabled: (boolean) If true then it shows the step-lines going from one bar to another.

stepLines.startColorStop: (number) Used as the offset value in the first addColorStop method call.

stepLines.startColor: (string) Used as the color value in the first addColorStop method call.

stepLines.endColorStop: (number) Used as the offset value in the second addColorStop method call.

stepLines.endColor: (string) Used as the color value in the second addColorStop method call.

Internals

This plugin uses a _status property on the options.plugins.waterFallPlugin to track when to draw the stepLines after any animations complete. Don't overwrite this.

Caveats

• This plugin presumes that each of yours bars in your chart match up either at the top or the bottom of each bar. If they don't the step lines going from one bar to the next will not be horizontal.

• The invisible dummy stacks are removed from the tooltip and legend by default using the filter mehthod. If you are providing your own filter method, using a custom tooltip or legend of your own then you will have to manually hide them because it will overwrite this plugins.

E.g. This is how this plugin hides them, so you could do it this way:

  filter: function(legendItem, chartData) {
    var currentDataset = chartData.datasets[legendItem.datasetIndex];

    return !currentDataset.dummyStack;
  }