google-map-directions.html

<!-- Copyright (c) 2015 Google Inc. All rights reserved. -->

<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../google-apis/google-maps-api.html">

<!--
Provides the Google Maps API Directions Service to provide directions
between a `startAddress` and `endAddress`.

See https://developers.google.com/maps/documentation/javascript/directions for more
information on the API.

#### Example:

    <template is="dom-bind">
      <google-map-directions map="{{map}}"
          start-address="San Francisco"
          end-address="Mountain View"
          travel-mode="BICYCLING"
          waypoints='[{"location": "Palo Alto"}, {"location": "San Mateo"}]'></google-map-directions>
      <google-map map="{{map}}" latitude="37.779"
                  longitude="-122.3892"></google-map>
    </template>

-->

<dom-module id="google-map-directions">
  <template>
    <style>
      :host {
        display: none;
      }
    </style>

    <google-maps-api
      api-key="[[apiKey]]"
      language="[[language]]"
      on-api-load="_mapApiLoaded"
      maps-url="[[mapsUrl]]">
    </google-maps-api>
  </template>
  <script>
    Polymer({
      is: 'google-map-directions',

      /**
       * Fired whenever the directions service returns a result.
       *
       * @event google-map-response
       * @param {{response: Object}} detail
       */

      /**
       * Polymer properties for the google-map-directions custom element.
       */
      properties: {
        /**
         * A Maps API key. To obtain an API key, see developers.google.com/maps/documentation/javascript/tutorial#api_key.
         */
        apiKey: String,

        /**
         * Overrides the origin the Maps API is loaded from. Defaults to `https://maps.googleapis.com`.
         */
        mapsUrl: {
          type: String
          // Initial value set in google-maps-api.
        },

        /**
         * The Google map object.
         *
         * @type google.maps.Map
         */
        map: {
          type: Object,
          observer: '_mapChanged'
        },

        /**
         * Start address or latlng to get directions from.
         *
         * @type string|google.maps.LatLng
         */
        startAddress: {
          type: String,
          value: null
        },

        /**
         * End address or latlng for directions to end.
         *
         * @type string|google.maps.LatLng
         */
        endAddress: {
          type: String,
          value: null
        },

        /**
         * Travel mode to use.  One of 'DRIVING', 'WALKING', 'BICYCLING', 'TRANSIT'.
         */
        travelMode: {
          type: String,
          value: 'DRIVING'
        },

        /**
         * Array of intermediate waypoints. Directions will be calculated
         * from the origin to the destination by way of each waypoint in this array.
         * The maximum allowed waypoints is 8, plus the origin, and destination.
         * Maps API for Business customers are allowed 23 waypoints,
         * plus the origin, and destination.
         * Waypoints are not supported for transit directions. Optional.
         *
         * @type Array<google.maps.DirectionsWaypoint>
         */
         waypoints: {
           type: Array,
           value: function() { return []; }
         },

        /**
         * The localized language to load the Maps API with. For more information
         * see https://developers.google.com/maps/documentation/javascript/basics#Language
         *
         * Note: the Maps API defaults to the preffered language setting of the browser.
         * Use this parameter to override that behavior.
         */
        language: {
          type: String,
          value: null
        },

        /**
         * Options for the display of results
         */
        rendererOptions: {
          type: Object,
          value: function() { return {}; }
        },

        /**
         * The response from the directions service.
         *
         */
        response: {
          type: Object,
          observer: '_responseChanged',
          notify: true
        }
      },

      observers: [
        '_route(startAddress, endAddress, travelMode, waypoints.*)'
      ],

      _mapApiLoaded: function() {
        this._route();
      },

      _responseChanged: function() {
        if (this.directionsRenderer && this.response) {
          this.directionsRenderer.setDirections(this.response);
        }
      },

      _mapChanged: function() {
        if (this.map && this.map instanceof google.maps.Map) {
          if (!this.directionsRenderer) {
            this.directionsRenderer = new google.maps.DirectionsRenderer(this.rendererOptions);
          }
          this.directionsRenderer.setMap(this.map);
          this._responseChanged();
        } else {
          // If there is no more map, remove the directionsRenderer from the map and delete it.
          if (this.directionsRenderer) {
            this.directionsRenderer.setMap(null);
            this.directionsRenderer = null;
          }
        }
      },

      _route: function() {
        // Abort attempts to _route if the API is not available yet or the
        // required attributes are blank.
        if (typeof google == 'undefined' || typeof google.maps == 'undefined' ||
            !this.startAddress || !this.endAddress) {
          return;
        }

        // Construct a directionsService if necessary.
        // Wait until here where the maps api has loaded and directions are actually needed.
        if (!this.directionsService) {
          this.directionsService = new google.maps.DirectionsService();
        }

        var request = {
          origin: this.startAddress,
          destination: this.endAddress,
          travelMode: this.travelMode,
          waypoints: this.waypoints
        };
        this.directionsService.route(request, function(response, status) {
          if (status == google.maps.DirectionsStatus.OK) {
            this.response = response;
            this.fire('google-map-response', {response: response});
          }
        }.bind(this));
      }
    });
  </script>
</dom-module>