Index: lib/common.js
===================================================================
--- a/lib/common.js
+++ b/lib/common.js
@@ -59,17 +59,17 @@
     // remove trailing wildcards
     .replace(/(\.\*)$/, "");
 }
 
 exports.filterToRegExp = filterToRegExp;
 
 function splitSelector(selector)
 {
-  if (selector.indexOf(",") == -1)
+  if (!selector.includes(","))
     return [selector];
 
   let selectors = [];
   let start = 0;
   let level = 0;
   let sep = "";
 
   for (let i = 0; i < selector.length; i++)
Index: lib/downloader.js
===================================================================
--- a/lib/downloader.js
+++ b/lib/downloader.js
@@ -202,17 +202,17 @@
    * @param {Downloadable} downloadable
    * @return {string}
    */
   getDownloadUrl(downloadable)
   {
     const {addonName, addonVersion, application, applicationVersion,
            platform, platformVersion} = require("info");
     let url = downloadable.redirectURL || downloadable.url;
-    if (url.indexOf("?") >= 0)
+    if (url.includes("?"))
       url += "&";
     else
       url += "?";
     // We limit the download count to 4+ to keep the request anonymized
     let {downloadCount} = downloadable;
     if (downloadCount > 4)
       downloadCount = "4+";
     url += "addonName=" + encodeURIComponent(addonName) +
Index: lib/filterClasses.js
===================================================================
--- a/lib/filterClasses.js
+++ b/lib/filterClasses.js
@@ -736,17 +736,17 @@
   let matchCase = null;
   let domains = null;
   let sitekeys = null;
   let thirdParty = null;
   let collapse = null;
   let csp = null;
   let rewrite = null;
   let options;
-  let match = (text.indexOf("$") >= 0 ? Filter.optionsRegExp.exec(text) : null);
+  let match = text.includes("$") ? Filter.optionsRegExp.exec(text) : null;
   if (match)
   {
     options = match[1].split(",");
     text = match.input.substr(0, match.index);
     for (let option of options)
     {
       let value = null;
       let separatorIndex = option.indexOf("=");