sparql.js

var fetch
if (typeof window !== 'undefined') {
  fetch = window.fetch
} else {
  fetch = require('isomorphic-fetch')
}

export default function (endpoint, query, options) {
  var url = endpoint + '?query=' + encodeURIComponent(query)

  var defaultOptions = {
    method: 'GET',
    headers: {
      'Accept': 'application/sparql-results+json'
    }
  }

  Object.assign(defaultOptions, options)

  return fetch(url, defaultOptions)
    .then(function (response) {
      return response.json()
    })
    .then(parseResponse)
};

var xmlSchema = 'http://www.w3.org/2001/XMLSchema#'

function parseResponse (body) {
  return body.results.bindings.map(function (row) {
    var rowObject = {}
    Object.keys(row).forEach(function (column) {
      rowObject[column] = dataTypeToJS(row[column])
    })
    return rowObject
  })
}

function dataTypeToJS (value) {
  var v = value.value
  if (typeof value.datatype === 'string') {
    var dt = value.datatype.replace(xmlSchema, '')
    switch (dt) {
      case 'string':
        v = String(v); break
      case 'boolean':
        v = Boolean(v === 'false' ? false : v); break
      case 'float':
      case 'integer':
      case 'long':
      case 'double':
      case 'decimal':
      case 'nonPositiveInteger':
      case 'nonNegativeInteger':
      case 'negativeInteger':
      case 'int':
      case 'unsignedLong':
      case 'positiveInteger':
      case 'short':
      case 'unsignedInt':
      case 'byte':
      case 'unsignedShort':
      case 'unsignedByte':
        v = Number(v); break
      case 'date':
      case 'time':
      case 'dateTime':
        v = new Date(v); break
    }
  }
  return v
}