Merge pull request #27 from macbre/duplicated-selectors

Report duplicated selectors

README.md

@@ -50,6 +50,7 @@ new analyzer('.foo {margin: 0 !important}', function(err, results) {
     "comments": 1,
     "commentsLength": 68,
     "complexSelectors": 32,
+    "duplicatedSelectors": 7,
     "emptyRules": 0,
     "oldIEFixes": 51,
     "importants": 3,
@@ -86,6 +87,7 @@ new analyzer('.foo {margin: 0 !important}', function(err, results) {
 * **comments**: number of comments in CSS source
 * **commentsLength**: length of comments content in CSS source
 * **complexSelectors**: number of complex selectors (consisting of more than three expressions, e.g. ``header ul li .foo``)
+* **duplicatedSelectors**: number of CSS selectors defined more than once in CSS source
 * **emptyRules**: number of rules with no properties (e.g. ``.foo { }``)
 * **oldIEFixes**: number of fixes for old versions of Internet Explorer (e.g. ``* html .foo {}`` and ``.foo { *zoom: 1 }``, [read](http://blogs.msdn.com/b/ie/archive/2005/09/02/460115.aspx) [more](http://www.impressivewebs.com/ie7-ie8-css-hacks/))
 * **importants**: number of properties with value forced by ``!important``

lib/collection.js

@@ -0,0 +1,45 @@
+/**
+ * Push items and count them
+ */
+function collection() {
+	this.items = {};
+}
+
+collection.prototype = {
+	push: function(item) {
+		if (typeof this.items[item] === 'undefined') {
+			this.items[item] = {
+				cnt: 1
+			};
+		}
+		else {
+			this.items[item].cnt++;
+		}
+	},
+
+	sort: function() {
+		var newItems = {},
+			sortedKeys;
+
+		// sort in descending order (by cnt)
+		sortedKeys = Object.keys(this.items).sort((function(a, b) {
+			return this.items[b].cnt - this.items[a].cnt;
+		}).bind(this));
+
+		// build new items dictionary
+		sortedKeys.forEach(function(key) {
+			newItems[key] = this.items[key];
+		}, this);
+
+		this.items = newItems;
+		return this;
+	},
+
+	forEach: function(callback) {
+		Object.keys(this.items).forEach(function(key) {
+			callback(key, this.items[key].cnt);
+		}, this);
+	}
+};
+
+module.exports = collection;

rules/duplicated.js

@@ -0,0 +1,24 @@
+var collection = require('../lib/collection'),
+	format = require('util').format;
+
+function rule(analyzer) {
+	var selectors = new collection();
+
+	analyzer.setMetric('duplicatedSelectors');
+
+	analyzer.on('rule', function(rule) {
+		selectors.push(rule.selectors.join(', '));
+	});
+
+	analyzer.on('report', function() {
+		selectors.sort().forEach(function(selector, cnt) {
+			if (cnt > 1) {
+				analyzer.incrMetric('duplicatedSelectors');
+				analyzer.addOffender('duplicatedSelectors', format('%s (%d times)', selector, cnt));
+			}
+		});
+	});
+}
+
+rule.description = 'Reports duplicated CSS selectors';
+module.exports = rule;

test/tests.js

@@ -36,6 +36,44 @@ tests = [
 		}
 	},
 
+	// duplicated selectors
+	{
+		css: '.foo { } .bar { }',
+		metrics: {
+			duplicatedSelectors: 0
+		}
+	},
+	{
+		css: '.foo, #bar { } .foo { }',
+		metrics: {
+			duplicatedSelectors: 0
+		}
+	},
+	{
+		css: '.foo { } .foo { }',
+		metrics: {
+			duplicatedSelectors: 1
+		}
+	},
+	{
+		css: '.foo { } .bar .foo { } .foo { }',
+		metrics: {
+			duplicatedSelectors: 1
+		}
+	},
+	{
+		css: '.foo { } .foo { } .foo { }',
+		metrics: {
+			duplicatedSelectors: 1
+		}
+	},
+	{
+		css: '.foo { } .bar { } .foo { } .bar { } #foo { } .bar { }',
+		metrics: {
+			duplicatedSelectors: 2
+		}
+	},
+
 	// empty rules
 	{
 		css: '.foo { } .bar { color: red } ',
@@ -293,7 +331,7 @@ testSelector = function(test) {
 					expectedMetrics = test.metrics;
 
 				Object.keys(expectedMetrics).forEach(function(metric) {
-					assert.equal(expectedMetrics[metric], actualMetrics[metric], metric + ' should equal ' + expectedMetrics[metric] + ' (was ' + actualMetrics[metric]  + ')');
+					assert.strictEqual(expectedMetrics[metric], actualMetrics[metric], metric + ' should equal ' + expectedMetrics[metric] + ' (got ' + actualMetrics[metric]  + ')');
 				});
 
 				done();