text: import distance from '@turf/distance';
  import { segmentReduce } from '@turf/meta';
  import { isObject } from '@turf/helpers';
  
  /**
   * Takes a {@link GeoJSON} and measures its length in the specified units, {@link (Multi)Point|Point}'s distance are ignored.
   *
   * @name length
   * @param {GeoJSON} geojson GeoJSON to measure
   * @param {Object} [options={}] Optional parameters
   * @param {string} [options.units=kilometers] can be degrees, radians, miles, or kilometers
   * @returns {number} length of GeoJSON
   * @example
   * var line = turf.lineString([[115, -32], [131, -22], [143, -25], [150, -34]]);
   * var length = turf.length(line, {units: 'miles'});
   *
   * //addToMap
   * var addToMap = [line];
   * line.properties.distance = length;
   */
  function length(geojson, options) {
      // Optional parameters
      options = options || {};
      if (!isObject(options)) throw new Error('options is invalid');
  
      // Input Validation
      if (!geojson) throw new Error('geojson is required');
  
      // Calculate distance from 2-vertex line segements
      return segmentReduce(geojson, function (previousValue, segment) {
          var coords = segment.geometry.coordinates;
          return previousValue + distance(coords[0], coords[1], options);
      }, 0);
  }
  
  export default length;
  