add some packages

node_modules/clean-css/lib/optimizer/level-2/remove-duplicates.js

@@ -0,0 +1,43 @@
+var Token = require('../../tokenizer/token');
+
+var serializeBody = require('../../writer/one-time').body;
+var serializeRules = require('../../writer/one-time').rules;
+
+function removeDuplicates(tokens) {
+  var matched = {};
+  var moreThanOnce = [];
+  var id, token;
+  var body, bodies;
+
+  for (var i = 0, l = tokens.length; i < l; i++) {
+    token = tokens[i];
+    if (token[0] != Token.RULE)
+      continue;
+
+    id = serializeRules(token[1]);
+
+    if (matched[id] && matched[id].length == 1)
+      moreThanOnce.push(id);
+    else
+      matched[id] = matched[id] || [];
+
+    matched[id].push(i);
+  }
+
+  for (i = 0, l = moreThanOnce.length; i < l; i++) {
+    id = moreThanOnce[i];
+    bodies = [];
+
+    for (var j = matched[id].length - 1; j >= 0; j--) {
+      token = tokens[matched[id][j]];
+      body = serializeBody(token[2]);
+
+      if (bodies.indexOf(body) > -1)
+        token[2] = [];
+      else
+        bodies.push(body);
+    }
+  }
+}
+
+module.exports = removeDuplicates;