Enum for checking built-in lib functions internally

src/ol/expr/expression.js

@@ -1,4 +1,5 @@
 goog.provide('ol.expr');
+goog.provide('ol.expr.functions');
 
 goog.require('ol.Extent');
 goog.require('ol.Feature');
@@ -83,9 +84,21 @@ ol.expr.isLibCall = function(expr) {
  * Library of well-known functions.  These are available to expressions parsed
  * with `ol.expr.parse`.
  *
- * @type {Object}
+ * @type {Object.<string, function(...)>}
  */
-ol.expr.lib = {
+ol.expr.lib = {};
+
+
+/**
+ * Enumeration of library function names.
+ *
+ * @enum {string}
+ */
+ol.expr.functions = {
+  EXTENT: 'extent',
+  GEOMETRY_TYPE: 'geometryType'
+};
+
 
 /**
  * Determine if a feature's extent intersects the provided extent.
@@ -96,7 +109,7 @@ ol.expr.lib = {
  * @return {boolean} The provided extent intersects the feature's extent.
  * @this {ol.Feature}
  */
-  'extent': function(minX, maxX, minY, maxY) {
+ol.expr.lib[ol.expr.functions.EXTENT] = function(minX, maxX, minY, maxY) {
   var intersects = false;
   var geometry = this.getGeometry();
   if (geometry) {
@@ -104,8 +117,10 @@ ol.expr.lib = {
         [minX, maxX, minY, maxY]);
   }
   return intersects;
-  },
+};
 
+    }
+  }
 
 /**
  * Determine if a feature's default geometry is of the given type.
@@ -113,13 +128,11 @@ ol.expr.lib = {
  * @return {boolean} The feature's default geometry is of the given type.
  * @this {ol.Feature}
  */
-  'geometryType': function(type) {
+ol.expr.lib[ol.expr.functions.GEOMETRY_TYPE] = function(type) {
   var same = false;
   var geometry = this.getGeometry();
   if (geometry) {
     same = geometry.getType() === type;
   }
   return same;
-  }
-
 };

src/ol/layer/vectorlayer.js

@@ -9,6 +9,7 @@ goog.require('ol.expr');
 goog.require('ol.expr.Literal');
 goog.require('ol.expr.Logical');
 goog.require('ol.expr.LogicalOp');
+goog.require('ol.expr.functions');
 goog.require('ol.geom.GeometryType');
 goog.require('ol.geom.SharedVertices');
 goog.require('ol.layer.Layer');
@@ -93,14 +94,14 @@ ol.layer.FeatureCache.prototype.getFeaturesObject = function(opt_expr) {
   } else {
     // check for geometryType or extent expression
     var name = ol.expr.isLibCall(opt_expr);
-    if (name === 'geometryType') {
+    if (name === ol.expr.functions.GEOMETRY_TYPE) {
       var args = /** @type {ol.expr.Call} */ (opt_expr).getArgs();
       goog.asserts.assert(args.length === 1);
       goog.asserts.assert(args[0] instanceof ol.expr.Literal);
       var type = /** @type {ol.expr.Literal } */ (args[0]).evaluate();
       goog.asserts.assertString(type);
       features = this.geometryTypeIndex_[type];
-    } else if (name === 'extent') {
+    } else if (name === ol.expr.functions.EXTENT) {
       var args = /** @type {ol.expr.Call} */ (opt_expr).getArgs();
       goog.asserts.assert(args.length === 4);
       var extent = [];
@@ -120,13 +121,13 @@ ol.layer.FeatureCache.prototype.getFeaturesObject = function(opt_expr) {
           for (var i = 0; i <= 1; ++i) {
             expr = expressions[i];
             name = ol.expr.isLibCall(expr);
-            if (name === 'geometryType') {
+            if (name === ol.expr.functions.GEOMETRY_TYPE) {
               args = /** @type {ol.expr.Call} */ (expr).getArgs();
               goog.asserts.assert(args.length === 1);
               goog.asserts.assert(args[0] instanceof ol.expr.Literal);
               type = /** @type {ol.expr.Literal } */ (args[0]).evaluate();
               goog.asserts.assertString(type);
-            } else if (name === 'extent') {
+            } else if (name === ol.expr.functions.EXTENT) {
               args = /** @type {ol.expr.Call} */ (expr).getArgs();
               goog.asserts.assert(args.length === 4);
               extent = [];