Improve Geolocation package.

examples/simple-map/.meteor/versions

@@ -25,7 +25,7 @@ jquery@1.0.1
 json@1.0.1
 livedata@1.0.11
 logging@1.0.4
-mdg:geolocation@1.0.2
+mdg:geolocation@1.0.3
 meteor-platform@1.1.2
 meteor@1.1.2
 minifiers@1.1.1

examples/simple-map/map.html

@@ -7,7 +7,12 @@ <h1>Where am I?</h1>
 
   <img src="http://maps.googleapis.com/maps/api/staticmap?center={{loc.lat}},{{loc.lng}}&zoom=15&size=600x300&maptype=roadmap&markers=color:blue%7C{{loc.lat}},{{loc.lng}}" />
 
+  <label class="high-accuracy">
+    <input type="checkbox" checked="{{highAccuracy}}" />
+    High accuracy position
+  </label>
+
   {{#if error}}
     <p>Error: {{error.message}}</p>
   {{/if}}
-</body>
+</body>

examples/simple-map/map.js

@@ -1,9 +1,22 @@
 if (Meteor.isClient) {
+  Template.body.events({
+    "change .high-accuracy input": function (event) {
+      Session.set("highAccuracy", event.target.checked);
+    }
+  });
   Template.body.helpers({
     loc: function () {
+      // options is *optional*.  We're including it in this demo
+      // to show how it is reactive.
+      var options = {
+        enableHighAccuracy: !!Session.get("highAccuracy")
+      };
       // return 0, 0 if the location isn't ready
-      return Geolocation.latLng() || { lat: 0, lng: 0 };
+      return Geolocation.latLng(options) || { lat: 0, lng: 0 };
     },
-    error: Geolocation.error
+    error: Geolocation.error,
+    highAccuracy: function() {
+      return Session.get("highAccuracy");
+    }
   });
-}
+}

packages/mdg:geolocation/README.md

@@ -10,10 +10,22 @@ There are currently no options to set. Every method is reactive using [Tracker](
 
 Returns the [position error](https://developer.mozilla.org/en-US/docs/Web/API/PositionError) that is currently preventing position updates.
 
-### Geolocation.currentLocation()
+### Geolocation.currentLocation(options)
 
 Returns the [position](https://developer.mozilla.org/en-US/docs/Web/API/Position) that is reported by the device, or null if no position is available.
 
-### Geolocation.latLng()
+The `options` parameter is optional; if provided it as if `Geolocation.setOptions` was called before returning the position.
 
-A simple shorthand for currentLocation() when all you need is the latitude and longitude. Returns an object that has `lat` and `lng` keys.
+### Geolocation.latLng(options)
+
+A simple shorthand for currentLocation() when all you need is the latitude and longitude. Returns an object that has `lat` and `lng` keys.
+
+The `options` parameter is optional; if provided it as if `Geolocation.setOptions` was called before returning the position.
+
+### Geolocation.setOptions(options)
+
+Provide [PositionOptions](https://developer.mozilla.org/en-US/docs/Web/API/PositionOptions) to manage power consumption on mobile devices.  The options can be reactive.
+
+### Geolocation.setPaused(boolean)
+
+If the parameter is `true`, temporarily halts reactive position updates to reduce power consumption.

packages/mdg:geolocation/geolocation.js

@@ -8,24 +8,53 @@ var location = new ReactiveVar(null);
 var error = new ReactiveVar(null);
 
 // options for watchPosition
-var options = {
+var options = new ReactiveVar({
   enableHighAccuracy: true,
   maximumAge: 0
-};
+}, function(a, b) {
+  // Reject attempts to set this to a non-object.
+  if (a == null || b == null || typeof a !== 'object' || typeof b !=='object') {
+    return true;
+  }
+  return (
+    a.enableHighAccuracy === b.enableHighAccuracy &&
+    a.maximumAge === b.maximumAge &&
+    a.timeout === b.timeout
+  );
+});
+
+// pause geolocation updates
+var paused = new ReactiveVar(false);
 
 var onError = function (newError) {
   error.set(newError);
+  Tracker.afterFlush(checkDependents);
 };
 
 var onPosition = function (newLocation) {
   location.set(newLocation);
   error.set(null);
+  Tracker.afterFlush(checkDependents);
+};
+
+var checkDependents = function() {
+  if (location.dep.hasDependents() || error.dep.hasDependents()) {
+    return;
+  }
+  watchingPosition.stop();
+  watchingPosition = false;
 };
 
 var startWatchingPosition = function () {
-  if (! watchingPosition && navigator.geolocation) {
-    navigator.geolocation.watchPosition(onPosition, onError, options);
-    watchingPosition = true;
+  if (watchingPosition === false && navigator.geolocation) {
+    watchingPosition = Tracker.autorun(function() {
+      if (paused.get()) { return; }
+      var watchId =
+        navigator.geolocation.watchPosition(onPosition, onError, options.get());
+      Tracker.onInvalidate(function() {
+        navigator.geolocation.clearWatch(watchId);
+      });
+    });
   }
 };
 
@@ -43,29 +72,37 @@ Geolocation = {
    * that is currently preventing position updates.
    */
   error: function () {
-    startWatchingPosition();
+    Tracker.nonreactive(startWatchingPosition);
     return error.get();
   },
 
   /**
    * @summary Get the current location
+   * @param {PositionOptions} options Optional geolocation options
+   * @param {Boolean} options.enableHighAccuracy
+   * @param {Number} options.maximumAge
+   * @param {Number} options.timeout
    * @return {Position | null} The
    * [position](https://developer.mozilla.org/en-US/docs/Web/API/Position)
    * that is reported by the device, or null if no position is available.
    */
-  currentLocation: function () {
-    startWatchingPosition();
+  currentLocation: function (_options) {
+    if (_options != null) {
+      Geolocation.setOptions(_options);
+    }
+    Tracker.nonreactive(startWatchingPosition);
     return location.get();
   },
+
   // simple version of location; just lat and lng
-  
+
   /**
    * @summary Get the current latitude and longitude
    * @return {Object | null} An object with `lat` and `lng` properties,
    * or null if no position is available.
    */
-  latLng: function () {
-    var loc = Geolocation.currentLocation();
+  latLng: function (options) {
+    var loc = Geolocation.currentLocation(options);
 
     if (loc) {
       return {
@@ -75,5 +112,20 @@ Geolocation = {
     }
 
     return null;
+  },
+
+  /**
+   * @summary Set the PositionOptions used for geolocation.
+   */
+  setOptions: function(_options) {
+    options.set(_options);
+  },
+
+  /**
+   * @summary Allow temporarily halting reactive updates to position.
+   */
+  setPaused: function(_paused) {
+    paused.set(_paused);
   }
-};
+
+};

packages/mdg:geolocation/package.js

@@ -1,7 +1,7 @@
 Package.describe({
   name: "mdg:geolocation",
   summary: "Provides reactive geolocation on desktop and mobile.",
-  version: "1.0.2",
+  version: "1.0.3",
   git: "https://github.com/meteor/mobile-packages"
 });
 
@@ -14,4 +14,4 @@ Package.on_use(function (api) {
   api.versionsFrom("METEOR@0.9.2");
   api.add_files(["geolocation.js"], "client");
   api.export("Geolocation", "client");
-});
+});