npm package: @kalisio/leaflet.donutcluster
Description: Plugin to display donut charts instead of circles in map when using Leaflet marker cluster
Author: Kalisio
Latest version: 1.1.0

Leaflet.DonutCluster
=====================

> forked from [akq/Leaflet.DonutCluster](https://github.com/akq/Leaflet.DonutCluster)

A lightweight standalone [Leaflet](https://leafletjs.com) plugin to display donut charts instead of circles in map when using [Leaflet marker cluster](https://github.com/Leaflet/Leaflet.markercluster). This lib copies the codes which generate the donut svg from [donutjs](https://github.com/finom/donutjs).

**Only depends on Leaflet and Leaflet.markercluster, NOT on other chart library like d3.js**

- [Online Demo -- basic](https://jsfiddle.net/b43c1xkf/1/embedded/result,html/)
- [Online Demo -- sum by field](https://jsfiddle.net/mfxd015b/3/embedded/result,html/)
- [Online Demo -- total by field](https://jsfiddle.net/kdL4gu6f/embedded/result,html/)

![cluster map example](screenshot.png)

## Usage

First install using `npm install @kalisio/leaflet.donutcluster` or `yarn add @kalisio/leaflet.donutcluster` and import in your project:
```javascript
import '@kalisio/leaflet.donutcluster/src/Leaflet.DonutCluster.css'
import '@kalisio/leaflet.donutcluster/src/Leaflet.DonutCluster.js'
```
You can also directly include `Leaflet.DonutCluster.js` and `Leaflet.DonutCluster.css` in your HTML pages.

Then use `L.DonutCluster` to create a marker cluster instance with options:
```javascript
// Create the markercluster
var markers = L.DonutCluster(
    // The first parameter is the standard marker cluster's configuration.
    {
        chunkedLoading: true
    }
    // The second parameter is the donut cluster's configuration.
    , {
        // Mandotary, indicates the field to group items by in order to create donut' sections.
        key: 'title',
        // Optional, indicates the value field to compute the "weight" of each donut section, ie item group.
        // If not given each item is assumed to have a value of 1 and the weight will be thus equal to item count of the group.
        // The size of each donut section is related to the weight of the group vs the sum of all weights.
        sumField: 'value',
        // Optional, indicates the value field to compute a "maximum weight" of each donut section, ie item group.
        // If given the size of each donut section will be related to the weight of the group vs the sum of maximum weights.
        totalField: 'maxValue',
        // Optional, indicates the group order.
        order: ['A', 'D', 'B', 'C'],
        // Optional, indicates the group IDs, when it is an array, the order option must be specified.
        // Otherwise use an object like `{ A: 'Type A', D: 'Type D', B: 'Type B', C: 'Type C' }``
        title: ['Type A','Type D','Type B','Type C' ],
        // Mandotary, the arc color for each donut section.
        // If array of colors will loop over it to pick color of each section sequentially.
        arcColorDict: {
            A: 'red',
            B: 'blue',
            C: 'yellow',
            D: 'black'
        },
        // Optional, the style of the donut
        style: {
            size: 40,
            fill: '#99d8c9',
            opacity: 1,
            weight: 7
        },
        // A class to assign to the donut center text
        textClassName: 'donut-text',
        // The value to be displayed in the donut center text
        // Could be `count`, `total` or `sum` (defaults).
        textContent: 'count',
        // If lodash is available text content can be based on a template.
        textTemplate: '<%= data.active.value %>/<%= sum %>',
        // A class to assign to the donut legend text on mouse hover
        legendClassName: 'donut-legend',
        // The value to be displayed in the donut legend text on mouse hover
        // Could be `percentage` or `value` (defaults).
        legendContent: 'value',
        // If lodash is available legend HTML content can be based on a template.
        legendTemplate: '<span style="border: 2px solid <%= color %>;"><%= selected.title %>:&nbsp;<%= selected.value %></span>',
        // Set this to true to avoid displaying legend on mouse over
        hideLegend: true,
        // Function used to format value numbers for display
        // Possible types are `count`, `percentage` or `value` and can help to use different formattings
        format: (value, type) => value.toFixed(0),
        // Function used to customize legend output
        getLegend: (title, color, percentage, value) => `<span>${title}:&nbsp;${percentage}%</span>`
    }
)
```
Then add the marker into the marker cluster:
```javascript
var marker = L.marker(L.latLng(a[0], a[1]), {
    title: title // the value to group
});

...

markers.addLayer(marker);
```

> Note: when the markers are created from a Leaflet GeoJson layer you can also directly reference properties of the underlying feature instead of marker options

## License

Licensed under the [MIT license](LICENSE).

## Authors

This project is sponsored by 

[![Kalisio](https://s3.eu-central-1.amazonaws.com/kalisioscope/kalisio/kalisio-logo-black-256x84.png)](https://kalisio.com)