Store the feature's commonly used id

To not clobber the feature's attributes, this is a separate
member property.

examples/vector-layer.js

@@ -48,7 +48,7 @@ map.on(['click', 'mousemove'], function(evt) {
     success: function(features) {
       var info = [];
       for (var i = 0, ii = features.length; i < ii; ++i) {
-        info.push(features[i].get('name'));
+        info.push(features[i].getFeatureId() + ': ' + features[i].get('name'));
       }
       document.getElementById('info').innerHTML = info.join(', ') || '&nbsp;';
     }

src/ol/feature.exports

@@ -1,7 +1,9 @@
 @exportSymbol ol.Feature
 @exportProperty ol.Feature.prototype.get
 @exportProperty ol.Feature.prototype.getAttributes
+@exportProperty ol.Feature.prototype.getFeatureId
 @exportProperty ol.Feature.prototype.getGeometry
 @exportProperty ol.Feature.prototype.set
+@exportProperty ol.Feature.prototype.setFeatureId
 @exportProperty ol.Feature.prototype.setGeometry
 @exportProperty ol.Feature.prototype.setSymbolizers

src/ol/feature.js

@@ -14,6 +14,12 @@ ol.Feature = function(opt_values) {
 
   goog.base(this, opt_values);
 
+  /**
+   * @type {string|undefined}
+   * @private
+   */
+  this.featureId_;
+
   /**
    * @type {string|undefined}
    * @private
@@ -46,6 +52,17 @@ ol.Feature.prototype.getAttributes = function() {
 };
 
 
+/**
+ * Returns the feature's commonly used identifier. This identifier is usually
+ * the unique id in the source store.
+ *
+ * @return {string|undefined} The feature's identifier.
+ */
+ol.Feature.prototype.getFeatureId = function() {
+  return this.featureId_;
+};
+
+
 /**
  * @return {ol.geom.Geometry} The geometry (or null if none).
  */
@@ -85,6 +102,17 @@ ol.Feature.prototype.set = function(key, value) {
 };
 
 
+/**
+ * Set the feature's commonly used identifier. This identifier is usually the
+ * unique id in the source store.
+ *
+ * @param {string} featureId The feature's identifier.
+ */
+ol.Feature.prototype.setFeatureId = function(featureId) {
+  this.featureId_ = featureId;
+};
+
+
 /**
  * @param {ol.geom.Geometry} geometry The geometry.
  */

src/ol/parser/geojson.js

@@ -129,6 +129,9 @@ ol.parser.GeoJSON.prototype.parseFeature_ = function(json, opt_options) {
       geometry = null,
       options = opt_options || {};
   var feature = new ol.Feature(json.properties);
+  if (goog.isDef(json.id)) {
+    feature.setFeatureId(json.id);
+  }
   if (geomJson) {
     var type = geomJson.type;
     var callback = options.callback;

test/spec/ol/feature.test.js

@@ -16,6 +16,12 @@ describe('ol.Feature', function() {
       expect(feature.get('foo')).to.be('bar');
     });
 
+    it('can store the feature\'s commonly used id', function() {
+      var feature = new ol.Feature();
+      feature.setFeatureId('foo');
+      expect(feature.getFeatureId()).to.be('foo');
+    });
+
     it('will set the default geometry', function() {
       var feature = new ol.Feature({
         loc: new ol.geom.Point([10, 20]),

test/spec/ol/parser/geojson.test.js

@@ -151,6 +151,7 @@ describe('ol.parser.GeoJSON', function() {
         var first = result[0];
         expect(first).to.be.a(ol.Feature);
         expect(first.get('name')).to.be('Afghanistan');
+        expect(first.getFeatureId()).to.be('AFG');
         var firstGeom = first.getGeometry();
         expect(firstGeom).to.be.a(ol.geom.Polygon);
         expect(ol.extent.equals(firstGeom.getBounds(),
@@ -160,6 +161,7 @@ describe('ol.parser.GeoJSON', function() {
         var last = result[178];
         expect(last).to.be.a(ol.Feature);
         expect(last.get('name')).to.be('Zimbabwe');
+        expect(last.getFeatureId()).to.be('ZWE');
         var lastGeom = last.getGeometry();
         expect(lastGeom).to.be.a(ol.geom.Polygon);
         expect(ol.extent.equals(lastGeom.getBounds(),