class / function pattern for chaining

segment-page.js

trailguide.models.segment('segment-2').fetch({
  success: function(segment, response, xhr) {
    var butt = new trailguide.views.details({
      model: segment,
      el: '#details'
    });
    butt.render();
  }
});

segment.js

trailguide.models.Segment = Backbone.Model.extend({

  urlRoot: '/db/segments/',

  parse: function (response, options) {
    var additional = {};
    additional.geometry = response.geometry;
    additional.projectedGeometry = trailguide.geoUtils.project(response.geometry);
    additional.jstsGeometry = trailguide.geoUtils.geojson2jsts(additional.projectedGeometry);

    return _.extend(additional, response.properties);
  },

  toJSON: function () {
    var keysToRemove = [
      'geometry',
      'projectedGeometry',
      'jstsGeometry',
      'leafletLayer'
    ];

    return {
      type: "Feature",
      properties: _.omit(this.attributes, keysToRemove),
      geometry: this.get('geometry')
    };
  },

  getDistance: function () {
    return this.get('jstsGeometry').getLength();
  },

  getEndpoints: function () {
    var coords = this.get('geometry').coordinates;
    endpoints = [coords[0], coords[coords.length - 1]];
    return endpoints;
  },

  getAdjacentTrailheads: function () {
    // get any trailheads corresponding with
    // this segment's endpoints
  },

  getAdjacentSegments: function () {
    // get any other segments corresponding with
    // this segment's endpoints
    var url = 'db/segments/_design/geo/_view/endpoints?keys=' + this.getEndpoints();
  },

  getPOIs: function() {
    // get POIs associated with this segment
    var poiIDs = this.get('pois');
  },

  getRelatedRoutes: function () {
    // get any routes that include this segment
  },

  leafletLayer: function (options) {
    options = options || {};
    return L.geoJson(this.toJSON(), options);
  },

  details: function () {
    // prepare the details object for
    // this segment's view
    var details = {
      'distance': this.getDistance()
    };

    var pois = this.get('pois');
    if (pois) {
      details.pois = pois;
    }

    var accessibility = this.get('accessibility');
    if (accessibility) {
      details.accessibility = accessibility;
    }

    return { 'details': details };
  }
});

trailguide.models.segment = function(segmentId) {
    return new trailguide.models.Segment({id: segmentId});
};