code: function transformFeature (feature, fields) {
    const attributes = {}
  
    // first transform each of the features to the converted field name and transformed value
    if (feature.attributes && Object.keys(feature.attributes)) {
      _.each(Object.keys(feature.attributes), (name) => {
        let attr = {}
        attr[name] = feature.attributes[name]
        try {
          attributes[fields[name].outName] = convertAttribute(attr, fields[name])
        } catch (e) {
          console.error('Field was missing from attribute')
        }
      })
    }
  
    return {
      type: 'Feature',
      properties: attributes,
      geometry: parseGeometry(feature.geometry)
    }
  }
docs: Converts a single feature from esri json to geojson
  
  @param {object} feature - a single esri feature
  @param {object} fields - the fields object from the service
  @returns {object} feature - a geojson feature
  @private