Bar graph added.

node_modules/vega-voronoi/build/vega-voronoi.js

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+(function (global, factory) {
+  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('vega-dataflow'), require('vega-util'), require('d3-delaunay')) :
+  typeof define === 'function' && define.amd ? define(['exports', 'vega-dataflow', 'vega-util', 'd3-delaunay'], factory) :
+  (global = global || self, factory((global.vega = global.vega || {}, global.vega.transforms = {}), global.vega, global.vega, global.d3));
+}(this, (function (exports, vegaDataflow, vegaUtil, d3Delaunay) { 'use strict';
+
+  function Voronoi(params) {
+    vegaDataflow.Transform.call(this, null, params);
+  }
+
+  Voronoi.Definition = {
+    'type': 'Voronoi',
+    'metadata': {'modifies': true},
+    'params': [
+      { 'name': 'x', 'type': 'field', 'required': true },
+      { 'name': 'y', 'type': 'field', 'required': true },
+      { 'name': 'size', 'type': 'number', 'array': true, 'length': 2 },
+      { 'name': 'extent', 'type': 'array', 'array': true, 'length': 2,
+        'default': [[-1e5, -1e5], [1e5, 1e5]],
+        'content': {'type': 'number', 'array': true, 'length': 2} },
+      { 'name': 'as', 'type': 'string', 'default': 'path' }
+    ]
+  };
+
+  const prototype = vegaUtil.inherits(Voronoi, vegaDataflow.Transform);
+
+  const defaultExtent = [-1e5, -1e5, 1e5, 1e5];
+
+  prototype.transform = function(_, pulse) {
+    const as = _.as || 'path',
+          data = pulse.source;
+
+    // nothing to do if no data
+    if (!data || !data.length) return pulse;
+
+    // configure and construct voronoi diagram
+    let s = _.size;
+    s = s ? [0, 0, s[0], s[1]]
+      : (s = _.extent) ? [s[0][0], s[0][1], s[1][0], s[1][1]]
+      : defaultExtent;
+
+    const voronoi = this.value = d3Delaunay.Delaunay.from(data, _.x, _.y).voronoi(s);
+
+    // map polygons to paths
+    for (let i=0, n=data.length; i<n; ++i) {
+      const polygon = voronoi.cellPolygon(i);
+      data[i][as] = polygon ? toPathString(polygon) : null;
+    }
+
+    return pulse.reflow(_.modified()).modifies(as);
+  };
+
+  // suppress duplicated end point vertices
+  function toPathString(p) {
+    const x = p[0][0],
+          y = p[0][1];
+
+    let n = p.length - 1;
+    for (; p[n][0] === x && p[n][1] === y; --n);
+
+    return 'M' + p.slice(0, n + 1).join('L') + 'Z';
+  }
+
+  exports.voronoi = Voronoi;
+
+  Object.defineProperty(exports, '__esModule', { value: true });
+
+})));

node_modules/vega-voronoi/build/vega-voronoi.min.js

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+!function(e,t){"object"==typeof exports&&"undefined"!=typeof module?t(exports,require("vega-dataflow"),require("vega-util"),require("d3-delaunay")):"function"==typeof define&&define.amd?define(["exports","vega-dataflow","vega-util","d3-delaunay"],t):t(((e=e||self).vega=e.vega||{},e.vega.transforms={}),e.vega,e.vega,e.d3)}(this,(function(e,t,n,a){"use strict";function r(e){t.Transform.call(this,null,e)}r.Definition={type:"Voronoi",metadata:{modifies:!0},params:[{name:"x",type:"field",required:!0},{name:"y",type:"field",required:!0},{name:"size",type:"number",array:!0,length:2},{name:"extent",type:"array",array:!0,length:2,default:[[-1e5,-1e5],[1e5,1e5]],content:{type:"number",array:!0,length:2}},{name:"as",type:"string",default:"path"}]};const o=n.inherits(r,t.Transform),i=[-1e5,-1e5,1e5,1e5];function l(e){const t=e[0][0],n=e[0][1];let a=e.length-1;for(;e[a][0]===t&&e[a][1]===n;--a);return"M"+e.slice(0,a+1).join("L")+"Z"}o.transform=function(e,t){const n=e.as||"path",r=t.source;if(!r||!r.length)return t;let o=e.size;o=o?[0,0,o[0],o[1]]:(o=e.extent)?[o[0][0],o[0][1],o[1][0],o[1][1]]:i;const f=this.value=a.Delaunay.from(r,e.x,e.y).voronoi(o);for(let e=0,t=r.length;e<t;++e){const t=f.cellPolygon(e);r[e][n]=t?l(t):null}return t.reflow(e.modified()).modifies(n)},e.voronoi=r,Object.defineProperty(e,"__esModule",{value:!0})}));