Bar graph added.

node_modules/vega-loader/build/vega-loader.js

@@ -0,0 +1,443 @@
+(function (global, factory) {
+  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports, require('vega-util'), require('d3-dsv'), require('topojson-client'), require('vega-format')) :
+  typeof define === 'function' && define.amd ? define(['exports', 'vega-util', 'd3-dsv', 'topojson-client', 'vega-format'], factory) :
+  (global = global || self, factory(global.vega = {}, global.vega, global.d3, global.topojson, global.vega));
+}(this, (function (exports, vegaUtil, d3Dsv, topojsonClient, vegaFormat) { 'use strict';
+
+  // Matches absolute URLs with optional protocol
+  //   https://...    file://...    //...
+  const protocol_re = /^([A-Za-z]+:)?\/\//;
+
+  // Matches allowed URIs. From https://github.com/cure53/DOMPurify/blob/master/src/regexp.js with added file://
+  const allowed_re = /^(?:(?:(?:f|ht)tps?|mailto|tel|callto|cid|xmpp|file|data):|[^a-z]|[a-z+.\-]+(?:[^a-z+.\-:]|$))/i; // eslint-disable-line no-useless-escape
+  const whitespace_re = /[\u0000-\u0020\u00A0\u1680\u180E\u2000-\u2029\u205f\u3000]/g; // eslint-disable-line no-control-regex
+
+
+  // Special treatment in node.js for the file: protocol
+  const fileProtocol = 'file://';
+
+  /**
+   * Factory for a loader constructor that provides methods for requesting
+   * files from either the network or disk, and for sanitizing request URIs.
+   * @param {function} fetch - The Fetch API for HTTP network requests.
+   *   If null or undefined, HTTP loading will be disabled.
+   * @param {object} fs - The file system interface for file loading.
+   *   If null or undefined, local file loading will be disabled.
+   * @return {function} A loader constructor with the following signature:
+   *   param {object} [options] - Optional default loading options to use.
+   *   return {object} - A new loader instance.
+   */
+  function loaderFactory(fetch, fs) {
+    return function(options) {
+      return {
+        options: options || {},
+        sanitize: sanitize,
+        load: load,
+        fileAccess: !!fs,
+        file: fileLoader(fs),
+        http: httpLoader(fetch)
+      };
+    };
+  }
+
+  /**
+   * Load an external resource, typically either from the web or from the local
+   * filesystem. This function uses {@link sanitize} to first sanitize the uri,
+   * then calls either {@link http} (for web requests) or {@link file} (for
+   * filesystem loading).
+   * @param {string} uri - The resource indicator (e.g., URL or filename).
+   * @param {object} [options] - Optional loading options. These options will
+   *   override any existing default options.
+   * @return {Promise} - A promise that resolves to the loaded content.
+   */
+  async function load(uri, options) {
+    const opt = await this.sanitize(uri, options),
+          url = opt.href;
+
+    return opt.localFile
+      ? this.file(url)
+      : this.http(url, options);
+  }
+
+  /**
+   * URI sanitizer function.
+   * @param {string} uri - The uri (url or filename) to sanity check.
+   * @param {object} options - An options hash.
+   * @return {Promise} - A promise that resolves to an object containing
+   *  sanitized uri data, or rejects it the input uri is deemed invalid.
+   *  The properties of the resolved object are assumed to be
+   *  valid attributes for an HTML 'a' tag. The sanitized uri *must* be
+   *  provided by the 'href' property of the returned object.
+   */
+  async function sanitize(uri, options) {
+    options = vegaUtil.extend({}, this.options, options);
+
+    const fileAccess = this.fileAccess,
+          result = {href: null};
+
+    let isFile, loadFile, base;
+
+    const isAllowed = allowed_re.test(uri.replace(whitespace_re, ''));
+
+    if (uri == null || typeof uri !== 'string' || !isAllowed) {
+      vegaUtil.error('Sanitize failure, invalid URI: ' + vegaUtil.stringValue(uri));
+    }
+
+    const hasProtocol = protocol_re.test(uri);
+
+    // if relative url (no protocol/host), prepend baseURL
+    if ((base = options.baseURL) && !hasProtocol) {
+      // Ensure that there is a slash between the baseURL (e.g. hostname) and url
+      if (!uri.startsWith('/') && base[base.length-1] !== '/') {
+        uri = '/' + uri;
+      }
+      uri = base + uri;
+    }
+
+    // should we load from file system?
+    loadFile = (isFile = uri.startsWith(fileProtocol))
+      || options.mode === 'file'
+      || options.mode !== 'http' && !hasProtocol && fileAccess;
+
+    if (isFile) {
+      // strip file protocol
+      uri = uri.slice(fileProtocol.length);
+    } else if (uri.startsWith('//')) {
+      if (options.defaultProtocol === 'file') {
+        // if is file, strip protocol and set loadFile flag
+        uri = uri.slice(2);
+        loadFile = true;
+      } else {
+        // if relative protocol (starts with '//'), prepend default protocol
+        uri = (options.defaultProtocol || 'http') + ':' + uri;
+      }
+    }
+
+    // set non-enumerable mode flag to indicate local file load
+    Object.defineProperty(result, 'localFile', {value: !!loadFile});
+
+    // set uri
+    result.href = uri;
+
+    // set default result target, if specified
+    if (options.target) {
+      result.target = options.target + '';
+    }
+
+    // set default result rel, if specified (#1542)
+    if (options.rel) {
+      result.rel = options.rel + '';
+    }
+
+    // provide control over cross-origin image handling (#2238)
+    // https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image
+    if (options.context === 'image' && options.crossOrigin) {
+      result.crossOrigin = options.crossOrigin + '';
+    }
+
+    // return
+    return result;
+  }
+
+  /**
+   * File system loader factory.
+   * @param {object} fs - The file system interface.
+   * @return {function} - A file loader with the following signature:
+   *   param {string} filename - The file system path to load.
+   *   param {string} filename - The file system path to load.
+   *   return {Promise} A promise that resolves to the file contents.
+   */
+  function fileLoader(fs) {
+    return fs
+      ? function(filename) {
+          return new Promise(function(accept, reject) {
+            fs.readFile(filename, function(error, data) {
+              if (error) reject(error);
+              else accept(data);
+            });
+          });
+        }
+      : fileReject;
+  }
+
+  /**
+   * Default file system loader that simply rejects.
+   */
+  async function fileReject() {
+    vegaUtil.error('No file system access.');
+  }
+
+  /**
+   * HTTP request handler factory.
+   * @param {function} fetch - The Fetch API method.
+   * @return {function} - An http loader with the following signature:
+   *   param {string} url - The url to request.
+   *   param {object} options - An options hash.
+   *   return {Promise} - A promise that resolves to the file contents.
+   */
+  function httpLoader(fetch) {
+    return fetch
+      ? async function(url, options) {
+          const opt = vegaUtil.extend({}, this.options.http, options),
+                type = options && options.response,
+                response = await fetch(url, opt);
+
+          return !response.ok
+            ? vegaUtil.error(response.status + '' + response.statusText)
+            : vegaUtil.isFunction(response[type]) ? response[type]()
+            : response.text();
+        }
+      : httpReject;
+  }
+
+  /**
+   * Default http request handler that simply rejects.
+   */
+  async function httpReject() {
+    vegaUtil.error('No HTTP fetch method available.');
+  }
+
+  var typeParsers = {
+    boolean: vegaUtil.toBoolean,
+    integer: vegaUtil.toNumber,
+    number:  vegaUtil.toNumber,
+    date:    vegaUtil.toDate,
+    string:  vegaUtil.toString,
+    unknown: vegaUtil.identity
+  };
+
+  var typeTests = [
+    isBoolean,
+    isInteger,
+    isNumber,
+    isDate
+  ];
+
+  var typeList = [
+    'boolean',
+    'integer',
+    'number',
+    'date'
+  ];
+
+  function inferType(values, field) {
+    if (!values || !values.length) return 'unknown';
+
+    const n = values.length,
+          m = typeTests.length,
+          a = typeTests.map((_, i) => i + 1);
+
+    for (let i = 0, t = 0, j, value; i < n; ++i) {
+      value = field ? values[i][field] : values[i];
+      for (j = 0; j < m; ++j) {
+        if (a[j] && isValid(value) && !typeTests[j](value)) {
+          a[j] = 0;
+          ++t;
+          if (t === typeTests.length) return 'string';
+        }
+      }
+    }
+
+    return typeList[
+      a.reduce((u, v) => u === 0 ? v : u, 0) - 1
+    ];
+  }
+
+  function inferTypes(data, fields) {
+    return fields.reduce(function(types, field) {
+      types[field] = inferType(data, field);
+      return types;
+    }, {});
+  }
+
+  // -- Type Checks ----
+
+  function isValid(_) {
+    return _ != null && _ === _;
+  }
+
+  function isBoolean(_) {
+    return _ === 'true' || _ === 'false' || _ === true || _ === false;
+  }
+
+  function isDate(_) {
+    return !Number.isNaN(Date.parse(_));
+  }
+
+  function isNumber(_) {
+    return !Number.isNaN(+_) && !(_ instanceof Date);
+  }
+
+  function isInteger(_) {
+    return isNumber(_) && Number.isInteger(+_);
+  }
+
+  function delimitedFormat(delimiter) {
+    const parse = function(data, format) {
+      const delim = {delimiter: delimiter};
+      return dsv(data, format ? vegaUtil.extend(format, delim) : delim);
+    };
+
+    parse.responseType = 'text';
+
+    return parse;
+  }
+
+  function dsv(data, format) {
+    if (format.header) {
+      data = format.header
+        .map(vegaUtil.stringValue)
+        .join(format.delimiter) + '\n' + data;
+    }
+    return d3Dsv.dsvFormat(format.delimiter).parse(data + '');
+  }
+
+  dsv.responseType = 'text';
+
+  function isBuffer(_) {
+    return (typeof Buffer === 'function' && vegaUtil.isFunction(Buffer.isBuffer))
+      ? Buffer.isBuffer(_) : false;
+  }
+
+  function json(data, format) {
+    const prop = (format && format.property) ? vegaUtil.field(format.property) : vegaUtil.identity;
+    return vegaUtil.isObject(data) && !isBuffer(data)
+      ? parseJSON(prop(data))
+      : prop(JSON.parse(data));
+  }
+
+  json.responseType = 'json';
+
+  function parseJSON(data, format) {
+    return (format && format.copy)
+      ? JSON.parse(JSON.stringify(data))
+      : data;
+  }
+
+  const filters = {
+    interior: (a, b) => a !== b,
+    exterior: (a, b) => a === b
+  };
+
+  function topojson(data, format) {
+    let method, object, property, filter;
+    data = json(data, format);
+
+    if (format && format.feature) {
+      method = topojsonClient.feature;
+      property = format.feature;
+    } else if (format && format.mesh) {
+      method = topojsonClient.mesh;
+      property = format.mesh;
+      filter = filters[format.filter];
+    } else {
+      vegaUtil.error('Missing TopoJSON feature or mesh parameter.');
+    }
+
+    object = (object = data.objects[property])
+      ? method(data, object, filter)
+      : vegaUtil.error('Invalid TopoJSON object: ' + property);
+
+    return object && object.features || [object];
+  }
+
+  topojson.responseType = 'json';
+
+  const format = {
+    dsv: dsv,
+    csv: delimitedFormat(','),
+    tsv: delimitedFormat('\t'),
+    json: json,
+    topojson: topojson
+  };
+
+  function formats(name, reader) {
+    if (arguments.length > 1) {
+      format[name] = reader;
+      return this;
+    } else {
+      return vegaUtil.hasOwnProperty(format, name) ? format[name] : null;
+    }
+  }
+
+  function responseType(type) {
+    const f = formats(type);
+    return f && f.responseType || 'text';
+  }
+
+  function read(data, schema, timeParser, utcParser) {
+    schema = schema || {};
+
+    const reader = formats(schema.type || 'json');
+    if (!reader) vegaUtil.error('Unknown data format type: ' + schema.type);
+
+    data = reader(data, schema);
+    if (schema.parse) parse(data, schema.parse, timeParser, utcParser);
+
+    if (vegaUtil.hasOwnProperty(data, 'columns')) delete data.columns;
+    return data;
+  }
+
+  function parse(data, types, timeParser, utcParser) {
+    if (!data.length) return; // early exit for empty data
+
+    const locale = vegaFormat.timeFormatDefaultLocale();
+    timeParser = timeParser || locale.timeParse;
+    utcParser = utcParser || locale.utcParse;
+
+    var fields = data.columns || Object.keys(data[0]),
+        parsers, datum, field, i, j, n, m;
+
+    if (types === 'auto') types = inferTypes(data, fields);
+
+    fields = Object.keys(types);
+    parsers = fields.map(function(field) {
+      var type = types[field],
+          parts, pattern;
+
+      if (type && (type.startsWith('date:') || type.startsWith('utc:'))) {
+        parts = type.split(/:(.+)?/, 2);  // split on first :
+        pattern = parts[1];
+
+        if ((pattern[0] === '\'' && pattern[pattern.length-1] === '\'') ||
+            (pattern[0] === '"'  && pattern[pattern.length-1] === '"')) {
+          pattern = pattern.slice(1, -1);
+        }
+
+        const parse = parts[0] === 'utc' ? utcParser : timeParser;
+        return parse(pattern);
+      }
+
+      if (!typeParsers[type]) {
+        throw Error('Illegal format pattern: ' + field + ':' + type);
+      }
+
+      return typeParsers[type];
+    });
+
+    for (i=0, n=data.length, m=fields.length; i<n; ++i) {
+      datum = data[i];
+      for (j=0; j<m; ++j) {
+        field = fields[j];
+        datum[field] = parsers[j](datum[field]);
+      }
+    }
+  }
+
+  var loader = loaderFactory(
+    typeof fetch !== 'undefined' && fetch, // use built-in fetch API
+    null // no file system access
+  );
+
+  exports.format = format;
+  exports.formats = formats;
+  exports.inferType = inferType;
+  exports.inferTypes = inferTypes;
+  exports.loader = loader;
+  exports.read = read;
+  exports.responseType = responseType;
+  exports.typeParsers = typeParsers;
+
+  Object.defineProperty(exports, '__esModule', { value: true });
+
+})));

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

@@ -0,0 +1 @@
+!function(e,t){"object"==typeof exports&&"undefined"!=typeof module?t(exports,require("vega-util"),require("d3-dsv"),require("topojson-client"),require("vega-format")):"function"==typeof define&&define.amd?define(["exports","vega-util","d3-dsv","topojson-client","vega-format"],t):t((e=e||self).vega={},e.vega,e.d3,e.topojson,e.vega)}(this,(function(e,t,n,r,o){"use strict";const i=/^([A-Za-z]+:)?\/\//,s=/^(?:(?:(?:f|ht)tps?|mailto|tel|callto|cid|xmpp|file|data):|[^a-z]|[a-z+.\-]+(?:[^a-z+.\-:]|$))/i,u=/[\u0000-\u0020\u00A0\u1680\u180E\u2000-\u2029\u205f\u3000]/g;async function a(e,t){const n=await this.sanitize(e,t),r=n.href;return n.localFile?this.file(r):this.http(r,t)}async function f(e,n){n=t.extend({},this.options,n);const r=this.fileAccess,o={href:null};let a,f,c;const l=s.test(e.replace(u,""));null!=e&&"string"==typeof e&&l||t.error("Sanitize failure, invalid URI: "+t.stringValue(e));const p=i.test(e);return(c=n.baseURL)&&!p&&(e.startsWith("/")||"/"===c[c.length-1]||(e="/"+e),e=c+e),f=(a=e.startsWith("file://"))||"file"===n.mode||"http"!==n.mode&&!p&&r,a?e=e.slice("file://".length):e.startsWith("//")&&("file"===n.defaultProtocol?(e=e.slice(2),f=!0):e=(n.defaultProtocol||"http")+":"+e),Object.defineProperty(o,"localFile",{value:!!f}),o.href=e,n.target&&(o.target=n.target+""),n.rel&&(o.rel=n.rel+""),"image"===n.context&&n.crossOrigin&&(o.crossOrigin=n.crossOrigin+""),o}function c(e){return e?function(t){return new Promise((function(n,r){e.readFile(t,(function(e,t){e?r(e):n(t)}))}))}:l}async function l(){t.error("No file system access.")}function p(e){return e?async function(n,r){const o=t.extend({},this.options.http,r),i=r&&r.response,s=await e(n,o);return s.ok?t.isFunction(s[i])?s[i]():s.text():t.error(s.status+""+s.statusText)}:d}async function d(){t.error("No HTTP fetch method available.")}var h={boolean:t.toBoolean,integer:t.toNumber,number:t.toNumber,date:t.toDate,string:t.toString,unknown:t.identity},m=[function(e){return"true"===e||"false"===e||!0===e||!1===e},function(e){return b(e)&&Number.isInteger(+e)},b,function(e){return!Number.isNaN(Date.parse(e))}],g=["boolean","integer","number","date"];function y(e,t){if(!e||!e.length)return"unknown";const n=e.length,r=m.length,o=m.map((e,t)=>t+1);for(let s,u,a=0,f=0;a<n;++a)for(u=t?e[a][t]:e[a],s=0;s<r;++s)if(o[s]&&(null!=(i=u)&&i==i)&&!m[s](u)&&(o[s]=0,++f,f===m.length))return"string";var i;return g[o.reduce((e,t)=>0===e?t:e,0)-1]}function v(e,t){return t.reduce((function(t,n){return t[n]=y(e,n),t}),{})}function b(e){return!(Number.isNaN(+e)||e instanceof Date)}function j(e){const n=function(n,r){const o={delimiter:e};return N(n,r?t.extend(r,o):o)};return n.responseType="text",n}function N(e,r){return r.header&&(e=r.header.map(t.stringValue).join(r.delimiter)+"\n"+e),n.dsvFormat(r.delimiter).parse(e+"")}function O(e,n){const r=n&&n.property?t.field(n.property):t.identity;return!t.isObject(e)||(o=e,"function"==typeof Buffer&&t.isFunction(Buffer.isBuffer)&&Buffer.isBuffer(o))?r(JSON.parse(e)):function(e,t){return t&&t.copy?JSON.parse(JSON.stringify(e)):e}(r(e));var o}N.responseType="text",O.responseType="json";const x={interior:(e,t)=>e!==t,exterior:(e,t)=>e===t};function T(e,n){let o,i,s,u;return e=O(e,n),n&&n.feature?(o=r.feature,s=n.feature):n&&n.mesh?(o=r.mesh,s=n.mesh,u=x[n.filter]):t.error("Missing TopoJSON feature or mesh parameter."),i=(i=e.objects[s])?o(e,i,u):t.error("Invalid TopoJSON object: "+s),i&&i.features||[i]}T.responseType="json";const P={dsv:N,csv:j(","),tsv:j("\t"),json:O,topojson:T};function w(e,n){return arguments.length>1?(P[e]=n,this):t.hasOwnProperty(P,e)?P[e]:null}var z=function(e,t){return function(n){return{options:n||{},sanitize:f,load:a,fileAccess:!!t,file:c(t),http:p(e)}}}("undefined"!=typeof fetch&&fetch,null);e.format=P,e.formats=w,e.inferType=y,e.inferTypes=v,e.loader=z,e.read=function(e,n,r,i){const s=w((n=n||{}).type||"json");return s||t.error("Unknown data format type: "+n.type),e=s(e,n),n.parse&&function(e,t,n,r){if(!e.length)return;const i=o.timeFormatDefaultLocale();n=n||i.timeParse,r=r||i.utcParse;var s,u,a,f,c,l,p,d=e.columns||Object.keys(e[0]);"auto"===t&&(t=v(e,d));for(d=Object.keys(t),s=d.map((function(e){var o,i,s=t[e];if(s&&(s.startsWith("date:")||s.startsWith("utc:"))){return("'"===(i=(o=s.split(/:(.+)?/,2))[1])[0]&&"'"===i[i.length-1]||'"'===i[0]&&'"'===i[i.length-1])&&(i=i.slice(1,-1)),("utc"===o[0]?r:n)(i)}if(!h[s])throw Error("Illegal format pattern: "+e+":"+s);return h[s]})),f=0,l=e.length,p=d.length;f<l;++f)for(u=e[f],c=0;c<p;++c)a=d[c],u[a]=s[c](u[a])}(e,n.parse,r,i),t.hasOwnProperty(e,"columns")&&delete e.columns,e},e.responseType=function(e){const t=w(e);return t&&t.responseType||"text"},e.typeParsers=h,Object.defineProperty(e,"__esModule",{value:!0})}));

node_modules/vega-loader/build/vega-loader.node.js

@@ -0,0 +1,442 @@
+'use strict';
+
+Object.defineProperty(exports, '__esModule', { value: true });
+
+var vegaUtil = require('vega-util');
+var d3Dsv = require('d3-dsv');
+var topojsonClient = require('topojson-client');
+var vegaFormat = require('vega-format');
+
+// Matches absolute URLs with optional protocol
+//   https://...    file://...    //...
+const protocol_re = /^([A-Za-z]+:)?\/\//;
+
+// Matches allowed URIs. From https://github.com/cure53/DOMPurify/blob/master/src/regexp.js with added file://
+const allowed_re = /^(?:(?:(?:f|ht)tps?|mailto|tel|callto|cid|xmpp|file|data):|[^a-z]|[a-z+.\-]+(?:[^a-z+.\-:]|$))/i; // eslint-disable-line no-useless-escape
+const whitespace_re = /[\u0000-\u0020\u00A0\u1680\u180E\u2000-\u2029\u205f\u3000]/g; // eslint-disable-line no-control-regex
+
+
+// Special treatment in node.js for the file: protocol
+const fileProtocol = 'file://';
+
+/**
+ * Factory for a loader constructor that provides methods for requesting
+ * files from either the network or disk, and for sanitizing request URIs.
+ * @param {function} fetch - The Fetch API for HTTP network requests.
+ *   If null or undefined, HTTP loading will be disabled.
+ * @param {object} fs - The file system interface for file loading.
+ *   If null or undefined, local file loading will be disabled.
+ * @return {function} A loader constructor with the following signature:
+ *   param {object} [options] - Optional default loading options to use.
+ *   return {object} - A new loader instance.
+ */
+function loaderFactory(fetch, fs) {
+  return function(options) {
+    return {
+      options: options || {},
+      sanitize: sanitize,
+      load: load,
+      fileAccess: !!fs,
+      file: fileLoader(fs),
+      http: httpLoader(fetch)
+    };
+  };
+}
+
+/**
+ * Load an external resource, typically either from the web or from the local
+ * filesystem. This function uses {@link sanitize} to first sanitize the uri,
+ * then calls either {@link http} (for web requests) or {@link file} (for
+ * filesystem loading).
+ * @param {string} uri - The resource indicator (e.g., URL or filename).
+ * @param {object} [options] - Optional loading options. These options will
+ *   override any existing default options.
+ * @return {Promise} - A promise that resolves to the loaded content.
+ */
+async function load(uri, options) {
+  const opt = await this.sanitize(uri, options),
+        url = opt.href;
+
+  return opt.localFile
+    ? this.file(url)
+    : this.http(url, options);
+}
+
+/**
+ * URI sanitizer function.
+ * @param {string} uri - The uri (url or filename) to sanity check.
+ * @param {object} options - An options hash.
+ * @return {Promise} - A promise that resolves to an object containing
+ *  sanitized uri data, or rejects it the input uri is deemed invalid.
+ *  The properties of the resolved object are assumed to be
+ *  valid attributes for an HTML 'a' tag. The sanitized uri *must* be
+ *  provided by the 'href' property of the returned object.
+ */
+async function sanitize(uri, options) {
+  options = vegaUtil.extend({}, this.options, options);
+
+  const fileAccess = this.fileAccess,
+        result = {href: null};
+
+  let isFile, loadFile, base;
+
+  const isAllowed = allowed_re.test(uri.replace(whitespace_re, ''));
+
+  if (uri == null || typeof uri !== 'string' || !isAllowed) {
+    vegaUtil.error('Sanitize failure, invalid URI: ' + vegaUtil.stringValue(uri));
+  }
+
+  const hasProtocol = protocol_re.test(uri);
+
+  // if relative url (no protocol/host), prepend baseURL
+  if ((base = options.baseURL) && !hasProtocol) {
+    // Ensure that there is a slash between the baseURL (e.g. hostname) and url
+    if (!uri.startsWith('/') && base[base.length-1] !== '/') {
+      uri = '/' + uri;
+    }
+    uri = base + uri;
+  }
+
+  // should we load from file system?
+  loadFile = (isFile = uri.startsWith(fileProtocol))
+    || options.mode === 'file'
+    || options.mode !== 'http' && !hasProtocol && fileAccess;
+
+  if (isFile) {
+    // strip file protocol
+    uri = uri.slice(fileProtocol.length);
+  } else if (uri.startsWith('//')) {
+    if (options.defaultProtocol === 'file') {
+      // if is file, strip protocol and set loadFile flag
+      uri = uri.slice(2);
+      loadFile = true;
+    } else {
+      // if relative protocol (starts with '//'), prepend default protocol
+      uri = (options.defaultProtocol || 'http') + ':' + uri;
+    }
+  }
+
+  // set non-enumerable mode flag to indicate local file load
+  Object.defineProperty(result, 'localFile', {value: !!loadFile});
+
+  // set uri
+  result.href = uri;
+
+  // set default result target, if specified
+  if (options.target) {
+    result.target = options.target + '';
+  }
+
+  // set default result rel, if specified (#1542)
+  if (options.rel) {
+    result.rel = options.rel + '';
+  }
+
+  // provide control over cross-origin image handling (#2238)
+  // https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image
+  if (options.context === 'image' && options.crossOrigin) {
+    result.crossOrigin = options.crossOrigin + '';
+  }
+
+  // return
+  return result;
+}
+
+/**
+ * File system loader factory.
+ * @param {object} fs - The file system interface.
+ * @return {function} - A file loader with the following signature:
+ *   param {string} filename - The file system path to load.
+ *   param {string} filename - The file system path to load.
+ *   return {Promise} A promise that resolves to the file contents.
+ */
+function fileLoader(fs) {
+  return fs
+    ? function(filename) {
+        return new Promise(function(accept, reject) {
+          fs.readFile(filename, function(error, data) {
+            if (error) reject(error);
+            else accept(data);
+          });
+        });
+      }
+    : fileReject;
+}
+
+/**
+ * Default file system loader that simply rejects.
+ */
+async function fileReject() {
+  vegaUtil.error('No file system access.');
+}
+
+/**
+ * HTTP request handler factory.
+ * @param {function} fetch - The Fetch API method.
+ * @return {function} - An http loader with the following signature:
+ *   param {string} url - The url to request.
+ *   param {object} options - An options hash.
+ *   return {Promise} - A promise that resolves to the file contents.
+ */
+function httpLoader(fetch) {
+  return fetch
+    ? async function(url, options) {
+        const opt = vegaUtil.extend({}, this.options.http, options),
+              type = options && options.response,
+              response = await fetch(url, opt);
+
+        return !response.ok
+          ? vegaUtil.error(response.status + '' + response.statusText)
+          : vegaUtil.isFunction(response[type]) ? response[type]()
+          : response.text();
+      }
+    : httpReject;
+}
+
+/**
+ * Default http request handler that simply rejects.
+ */
+async function httpReject() {
+  vegaUtil.error('No HTTP fetch method available.');
+}
+
+var typeParsers = {
+  boolean: vegaUtil.toBoolean,
+  integer: vegaUtil.toNumber,
+  number:  vegaUtil.toNumber,
+  date:    vegaUtil.toDate,
+  string:  vegaUtil.toString,
+  unknown: vegaUtil.identity
+};
+
+var typeTests = [
+  isBoolean,
+  isInteger,
+  isNumber,
+  isDate
+];
+
+var typeList = [
+  'boolean',
+  'integer',
+  'number',
+  'date'
+];
+
+function inferType(values, field) {
+  if (!values || !values.length) return 'unknown';
+
+  const n = values.length,
+        m = typeTests.length,
+        a = typeTests.map((_, i) => i + 1);
+
+  for (let i = 0, t = 0, j, value; i < n; ++i) {
+    value = field ? values[i][field] : values[i];
+    for (j = 0; j < m; ++j) {
+      if (a[j] && isValid(value) && !typeTests[j](value)) {
+        a[j] = 0;
+        ++t;
+        if (t === typeTests.length) return 'string';
+      }
+    }
+  }
+
+  return typeList[
+    a.reduce((u, v) => u === 0 ? v : u, 0) - 1
+  ];
+}
+
+function inferTypes(data, fields) {
+  return fields.reduce(function(types, field) {
+    types[field] = inferType(data, field);
+    return types;
+  }, {});
+}
+
+// -- Type Checks ----
+
+function isValid(_) {
+  return _ != null && _ === _;
+}
+
+function isBoolean(_) {
+  return _ === 'true' || _ === 'false' || _ === true || _ === false;
+}
+
+function isDate(_) {
+  return !Number.isNaN(Date.parse(_));
+}
+
+function isNumber(_) {
+  return !Number.isNaN(+_) && !(_ instanceof Date);
+}
+
+function isInteger(_) {
+  return isNumber(_) && Number.isInteger(+_);
+}
+
+function delimitedFormat(delimiter) {
+  const parse = function(data, format) {
+    const delim = {delimiter: delimiter};
+    return dsv(data, format ? vegaUtil.extend(format, delim) : delim);
+  };
+
+  parse.responseType = 'text';
+
+  return parse;
+}
+
+function dsv(data, format) {
+  if (format.header) {
+    data = format.header
+      .map(vegaUtil.stringValue)
+      .join(format.delimiter) + '\n' + data;
+  }
+  return d3Dsv.dsvFormat(format.delimiter).parse(data + '');
+}
+
+dsv.responseType = 'text';
+
+function isBuffer(_) {
+  return (typeof Buffer === 'function' && vegaUtil.isFunction(Buffer.isBuffer))
+    ? Buffer.isBuffer(_) : false;
+}
+
+function json(data, format) {
+  const prop = (format && format.property) ? vegaUtil.field(format.property) : vegaUtil.identity;
+  return vegaUtil.isObject(data) && !isBuffer(data)
+    ? parseJSON(prop(data))
+    : prop(JSON.parse(data));
+}
+
+json.responseType = 'json';
+
+function parseJSON(data, format) {
+  return (format && format.copy)
+    ? JSON.parse(JSON.stringify(data))
+    : data;
+}
+
+const filters = {
+  interior: (a, b) => a !== b,
+  exterior: (a, b) => a === b
+};
+
+function topojson(data, format) {
+  let method, object, property, filter;
+  data = json(data, format);
+
+  if (format && format.feature) {
+    method = topojsonClient.feature;
+    property = format.feature;
+  } else if (format && format.mesh) {
+    method = topojsonClient.mesh;
+    property = format.mesh;
+    filter = filters[format.filter];
+  } else {
+    vegaUtil.error('Missing TopoJSON feature or mesh parameter.');
+  }
+
+  object = (object = data.objects[property])
+    ? method(data, object, filter)
+    : vegaUtil.error('Invalid TopoJSON object: ' + property);
+
+  return object && object.features || [object];
+}
+
+topojson.responseType = 'json';
+
+const format = {
+  dsv: dsv,
+  csv: delimitedFormat(','),
+  tsv: delimitedFormat('\t'),
+  json: json,
+  topojson: topojson
+};
+
+function formats(name, reader) {
+  if (arguments.length > 1) {
+    format[name] = reader;
+    return this;
+  } else {
+    return vegaUtil.hasOwnProperty(format, name) ? format[name] : null;
+  }
+}
+
+function responseType(type) {
+  const f = formats(type);
+  return f && f.responseType || 'text';
+}
+
+function read(data, schema, timeParser, utcParser) {
+  schema = schema || {};
+
+  const reader = formats(schema.type || 'json');
+  if (!reader) vegaUtil.error('Unknown data format type: ' + schema.type);
+
+  data = reader(data, schema);
+  if (schema.parse) parse(data, schema.parse, timeParser, utcParser);
+
+  if (vegaUtil.hasOwnProperty(data, 'columns')) delete data.columns;
+  return data;
+}
+
+function parse(data, types, timeParser, utcParser) {
+  if (!data.length) return; // early exit for empty data
+
+  const locale = vegaFormat.timeFormatDefaultLocale();
+  timeParser = timeParser || locale.timeParse;
+  utcParser = utcParser || locale.utcParse;
+
+  var fields = data.columns || Object.keys(data[0]),
+      parsers, datum, field, i, j, n, m;
+
+  if (types === 'auto') types = inferTypes(data, fields);
+
+  fields = Object.keys(types);
+  parsers = fields.map(function(field) {
+    var type = types[field],
+        parts, pattern;
+
+    if (type && (type.startsWith('date:') || type.startsWith('utc:'))) {
+      parts = type.split(/:(.+)?/, 2);  // split on first :
+      pattern = parts[1];
+
+      if ((pattern[0] === '\'' && pattern[pattern.length-1] === '\'') ||
+          (pattern[0] === '"'  && pattern[pattern.length-1] === '"')) {
+        pattern = pattern.slice(1, -1);
+      }
+
+      const parse = parts[0] === 'utc' ? utcParser : timeParser;
+      return parse(pattern);
+    }
+
+    if (!typeParsers[type]) {
+      throw Error('Illegal format pattern: ' + field + ':' + type);
+    }
+
+    return typeParsers[type];
+  });
+
+  for (i=0, n=data.length, m=fields.length; i<n; ++i) {
+    datum = data[i];
+    for (j=0; j<m; ++j) {
+      field = fields[j];
+      datum[field] = parsers[j](datum[field]);
+    }
+  }
+}
+
+var loader = loaderFactory(
+  require('node-fetch'),
+  require('fs')
+);
+
+exports.format = format;
+exports.formats = formats;
+exports.inferType = inferType;
+exports.inferTypes = inferTypes;
+exports.loader = loader;
+exports.read = read;
+exports.responseType = responseType;
+exports.typeParsers = typeParsers;