Strip Olytics trackers + ES2015 update (#41)

Author: waldoluisribeiro

.eslintrc

@@ -3,6 +3,9 @@
         "webextensions": true
     },
     "extends": "eslint:recommended",
+    "parserOptions": {
+        "ecmaVersion": 6
+    },
     "rules": {
         "accessor-pairs": "error",
         "array-bracket-newline": "error",

README.md

@@ -37,6 +37,10 @@ The following query string parameters are stripped:
   - `mc_eid`
 - [Marketo](https://www.marketo.com/)
   - `mkt_tok`
+- [Olytics](https://main.omeda.com/knowledge-base/olytics-product-outline/)
+  - `oly_anon_id`
+  - `oly_enc_id`
+  - `otc`
 - [Wicked Reports](https://www.wickedreports.com/)
   - `wickedid`
 - [Yandex](https://yandex.com/support/direct/statistics/)

background.js

@@ -3,26 +3,25 @@
  * parameter. We'll search the query string portion of the URL for this
  * pattern to determine if there's any stripping work to do.
  */
-var searchPattern = new RegExp('utm_|clid|_hs|icid|igshid|mc_|mkt_tok|yclid|_openstat|wicked', 'i');
+const searchPattern = new RegExp('utm_|clid|_hs|icid|igshid|mc_|mkt_tok|yclid|_openstat|wicked|otc|oly_', 'i');
 
 /*
  * Pattern matching the query string parameters (key=value) that will be
  * stripped from the final URL.
  */
-var replacePattern = new RegExp(
+const replacePattern = new RegExp(
     '([?&]' +
-    '(icid|mkt_tok|(g|fb)clid|igshid|_hs(enc|mi)|mc_[ce]id|utm_(source|medium|term|campaign|content|cid|reader|referrer|name|social|social-type)|yclid|_openstat|wickedid)' +
+    '(icid|mkt_tok|(g|fb)clid|igshid|_hs(enc|mi)|mc_[ce]id|utm_(source|medium|term|campaign|content|cid|reader|referrer|name|social|social-type)|yclid|_openstat|wickedid|otc|oly_(anon|enc)_id)' +
     '=[^&#]*)',
     'ig');
 
-chrome.webRequest.onBeforeRequest.addListener(function(details) {
-    var url = details.url;
-    var queryStringIndex = url.indexOf('?');
+chrome.webRequest.onBeforeRequest.addListener((details) => {
+    const url = details.url;
+    const queryStringIndex = url.indexOf('?');
     if (url.search(searchPattern) > queryStringIndex) {
-        var stripped = url.replace(replacePattern, '');
+        let stripped = url.replace(replacePattern, '');
         if (stripped.charAt(queryStringIndex) === '&') {
-            stripped = stripped.substr(0, queryStringIndex) + '?' +
-                stripped.substr(queryStringIndex + 1)
+            stripped = `${stripped.substr(0, queryStringIndex)}?${stripped.substr(queryStringIndex + 1)}`;
         }
         if (stripped != url) {
             return {redirectUrl: stripped};