DWE.File = {}

DWE.File.httpGET = function (url) {
  return new Promise(function (resolve, reject) {
    var xmlHttp = new XMLHttpRequest()

    xmlHttp.onreadystatechange = function() {
      if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
        resolve(xmlHttp.responseText)
      } else if (xmlHttp.readyState == 4 && xmlHttp.status >= 400) {
        reject(xmlHttp.responseText)
      }
    }

    xmlHttp.open('GET', url, true)
    xmlHttp.responseType = 'text'
    xmlHttp.send(null)
  })
}

DWE.File.loadJson = function (url) {
  return new Promise(function (resolve, reject) {
    var promise = DWE.File.httpGET(url)
    promise.then(function (data) {
      var json
      try {
        json = JSON.parse(data)
      } catch (e) {
        return reject(e)
      }

      resolve(json)
    }, reject)
  })
}