sg-heatmap/dist/plugins/leaflet.js

Open-source all-in-one Swiss Army knife tool for creating Choropleth maps

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = supportLeaflet;
function supportLeaflet(heatmap) {
  function initializeRenderer(colorScale) {
    var defaultStyle = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
    var addonStyle = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {};

    if (!window) throw new Error('Method initializeRenderer should only be called browser-side');
    if (!window.L) throw new Error('Leaflet not loaded');
    if ('renderer' in this) {
      console.log('Existing renderer replaced');
      this.renderer.remove();
    }

    this.colorScale = colorScale;

    this.renderer = window.L.geoJSON(null, {
      style: function style(feature) {
        var styleOptions = Object.assign({}, defaultStyle);
        var color = feature.properties.color;
        if (color) Object.assign(styleOptions, addonStyle, { fillColor: color });
        return styleOptions;
      }
    }).addData(this.children.map(function (c) {
      return {
        id: c.id,
        type: 'Feature',
        geometry: c.geometry,
        properties: Object.assign({}, c.properties, { color: null })
      };
    }));

    return this.renderer;
  }

  function render(stat) {
    var _this = this;

    var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};

    if (!this.renderer) throw new Error('Renderer has not been initialized');

    var colorScale = options.colorScale || this.colorScale;

    var _getStat = this.getStat(stat),
        statValues = _getStat.values,
        min = _getStat.min,
        max = _getStat.max;

    var domain = options.domain || [min, max];
    function normalize(value) {
      return (value - domain[0]) / (domain[1] - domain[0]);
    }

    this.renderer.eachLayer(function (layer) {
      var key = layer.feature.id;
      if (key in statValues) {
        var normalized = normalize(statValues[key]);
        var transformed = Math.pow(normalized, options.transform || 1);
        layer.feature.properties.color = colorScale(transformed);
      } else {
        layer.feature.properties.color = null;
      }
      _this.renderer.resetStyle(layer);
    });
  }

  heatmap.initializeRenderer = initializeRenderer.bind(heatmap);
  heatmap.render = render.bind(heatmap);
}