Ignore zoom for the filtered field when the value is the default one.

lib/carto/tree/definition.js

@@ -209,12 +209,14 @@ tree.Definition.prototype.toXML = function(env, existing) {
 };
 
 tree.Definition.prototype.toJS = function(env) {
+  var DEFAULT_ZOOM_VALUE = 8388607;
   var shaderAttrs = {};
   var frame_offset = this.frame_offset;
   var zoomFilter = "(" + this.zoom + " & (1 << ctx.zoom))";
   var filters = [zoomFilter];
   var originalFilters = this.filters.toJS(env);
-
+  // Ignore default zoom for filtering (https://github.com/CartoDB/carto/issues/40)
+  var zoomFiltered = this.zoom !== DEFAULT_ZOOM_VALUE;
   
   if (originalFilters) {
       filters.push(originalFilters);
@@ -235,8 +237,7 @@ tree.Definition.prototype.toJS = function(env) {
       exportedRule.symbolizer = rule.symbolizer;
       exportedRule.js = "if(" + filters.join(" && ") + "){" + rule.value.toJS(env) + "}";
       exportedRule.constant = rule.value.ev(env).is !== 'field';
-      exportedRule.filtered = originalFilters !== '';
-
+      exportedRule.filtered = zoomFiltered || (originalFilters !== '');
       shaderAttrs[rule.name] = shaderAttrs[rule.name] || [];
       shaderAttrs[rule.name].push(exportedRule);
   });

test/filtered.test.js

@@ -15,13 +15,15 @@
  *    marker-color: red; // 
  *   }
  * }
+ * 
+ * "zoom" is a special case, and it only should be considered when it's value is not the default. 
  */
 var assert = require('assert');
 var Carto = require('../lib/carto/index.js');
 var renderer = new Carto.RendererJS({ strict: true });
 
 
-describe('Field:filtered propery', function () {
+describe('property.filtered', function () {
     it('should be false when the property is not filtered', function () {
         var style = [
             '#layer {',
@@ -85,4 +87,17 @@ describe('Field:filtered propery', function () {
 
         assert(layers['marker-fill'].filtered);
     });
+
+    it('should be true when filtering by zoom', function () {
+        var style = [
+            '#layer {',
+            '   [zoom < 5]{',
+            '       marker-fill: blue;',
+            '    }',
+            '}`'
+        ].join('\n');
+        var layers = renderer.render(style).layers[0].shader;
+
+        assert(layers['marker-fill'].filtered);
+    });
 });