Common code for creating a style function

src/ol/feature.js

@@ -238,3 +238,38 @@ ol.feature.defaultStyleFunction = function(feature, resolution) {
   }
   return featureStyleFunction.call(feature, resolution);
 };
+
+
+/**
+ * Convert the provided object into a style function.  Functions passed through
+ * unchanged.  Arrays of ol.style.Style or single style objects wrapped in a
+ * new style function.
+ * @param {ol.feature.StyleFunction|Array.<ol.style.Style>|ol.style.Style} obj
+ *     A style function, a single style, or an array of styles.
+ * @return {ol.feature.StyleFunction} A style function.
+ */
+ol.feature.createStyleFunction = function(obj) {
+  /**
+   * @type {ol.feature.StyleFunction}
+   */
+  var styleFunction;
+
+  if (goog.isFunction(obj)) {
+    styleFunction = /** @type {ol.feature.StyleFunction} */ (obj);
+  } else {
+    /**
+     * @type {Array.<ol.style.Style>}
+     */
+    var styles;
+    if (goog.isArray(obj)) {
+      styles = obj;
+    } else {
+      goog.asserts.assertInstanceof(obj, ol.style.Style);
+      styles = [obj];
+    }
+    styleFunction = function(feature, resolution) {
+      return styles;
+    };
+  }
+  return styleFunction;
+};

src/ol/featureoverlay.js

@@ -10,7 +10,6 @@ goog.require('ol.CollectionEventType');
 goog.require('ol.Feature');
 goog.require('ol.feature');
 goog.require('ol.render.EventType');
-goog.require('ol.style.Style');
 
 
 
@@ -53,35 +52,12 @@ ol.FeatureOverlay = function(opt_options) {
    */
   this.postComposeListenerKey_ = null;
 
-  /**
-   * @type {ol.feature.StyleFunction}
-   */
-  var styleFunction;
-  if (goog.isDef(options.style)) {
-    if (goog.isFunction(options.style)) {
-      styleFunction = /** @type {ol.feature.StyleFunction} */ (options.style);
-    } else {
-      /**
-       * @type {Array.<ol.style.Style>}
-       */
-      var styles;
-      if (goog.isArray(options.style)) {
-        styles = options.style;
-      } else {
-        goog.asserts.assertInstanceof(options.style, ol.style.Style);
-        styles = [options.style];
-      }
-      styleFunction = function(feature, resolution) {
-        return styles;
-      };
-    }
-  }
-
   /**
    * @private
    * @type {ol.feature.StyleFunction|undefined}
    */
-  this.styleFunction_ = styleFunction;
+  this.styleFunction_ = goog.isDef(options.style) ?
+      ol.feature.createStyleFunction(options.style) : undefined;
 
   if (goog.isDef(options.features)) {
     if (goog.isArray(options.features)) {

src/ol/layer/vectorlayer.js

@@ -1,9 +1,7 @@
 goog.provide('ol.layer.Vector');
 
-goog.require('goog.asserts');
 goog.require('ol.feature');
 goog.require('ol.layer.Layer');
-goog.require('ol.style.Style');
 
 
 /**
@@ -30,31 +28,7 @@ ol.layer.Vector = function(opt_options) {
   goog.base(this, /** @type {olx.layer.LayerOptions} */ (options));
 
   if (goog.isDef(options.style)) {
-
-    /**
-     * @type {ol.feature.StyleFunction}
-     */
-    var styleFunction;
-
-    if (goog.isFunction(options.style)) {
-      styleFunction = /** @type {ol.feature.StyleFunction} */ (options.style);
-    } else {
-      /**
-       * @type {Array.<ol.style.Style>}
-       */
-      var styles;
-      if (goog.isArray(options.style)) {
-        styles = options.style;
-      } else {
-        goog.asserts.assertInstanceof(options.style, ol.style.Style);
-        styles = [options.style];
-      }
-      styleFunction = function(feature, resolution) {
-        return styles;
-      };
-    }
-
-    this.setStyleFunction(styleFunction);
+    this.setStyleFunction(ol.feature.createStyleFunction(options.style));
   }
 
 };

src/ol/source/imagevectorsource.js

@@ -12,7 +12,6 @@ goog.require('ol.render.canvas.ReplayGroup');
 goog.require('ol.renderer.vector');
 goog.require('ol.source.ImageCanvas');
 goog.require('ol.source.Vector');
-goog.require('ol.style.Style');
 goog.require('ol.vec.Mat4');
 
 
@@ -41,38 +40,13 @@ ol.source.ImageVector = function(options) {
    */
   this.source_ = options.source;
 
-
-  /**
-   * @type {ol.feature.StyleFunction}
-   */
-  var styleFunction;
-
-  if (goog.isDef(options.style)) {
-    if (goog.isFunction(options.style)) {
-      styleFunction = /** @type {ol.feature.StyleFunction} */ (options.style);
-    } else {
-      /**
-       * @type {Array.<ol.style.Style>}
-       */
-      var styles;
-      if (goog.isArray(options.style)) {
-        styles = options.style;
-      } else {
-        goog.asserts.assertInstanceof(options.style, ol.style.Style);
-        styles = [options.style];
-      }
-      styleFunction = function(feature, resolution) {
-        return styles;
-      };
-    }
-  }
-
   /**
    * @private
    * @type {!ol.feature.StyleFunction}
    */
-  this.styleFunction_ = goog.isDef(styleFunction) ?
-      styleFunction : ol.feature.defaultStyleFunction;
+  this.styleFunction_ = goog.isDef(options.style) ?
+      ol.feature.createStyleFunction(options.style) :
+      ol.feature.defaultStyleFunction;
 
   /**
    * @private

test/spec/ol/feature.test.js

@@ -209,8 +209,39 @@ describe('ol.Feature', function() {
 
 });
 
+describe('ol.feature.createStyleFunction()', function() {
+  var style = new ol.style.Style();
+
+  it('creates a style function from a single style', function() {
+    var styleFunction = ol.feature.createStyleFunction(style);
+    expect(styleFunction()).to.eql([style]);
+  });
+
+  it('creates a style function from an array of styles', function() {
+    var styleFunction = ol.feature.createStyleFunction([style]);
+    expect(styleFunction()).to.eql([style]);
+  });
+
+  it('passes through a function', function() {
+    var original = function() {
+      return [style];
+    };
+    var styleFunction = ol.feature.createStyleFunction(original);
+    expect(styleFunction).to.be(original);
+  });
+
+  it('throws on (some) unexpected input', function() {
+    expect(function() {
+      ol.feature.createStyleFunction({bogus: 'input'});
+    }).to.throwException();
+  });
+
+});
+
 
 goog.require('goog.events');
 goog.require('goog.object');
 goog.require('ol.Feature');
+goog.require('ol.feature');
 goog.require('ol.geom.Point');
+goog.require('ol.style.Style');