this fixes #1067 + partially fixes #1070

platform/chromium/vapi-background.js

@@ -824,7 +824,7 @@ vAPI.net.registerListeners = function() {
         // something else. Test case for "unfriendly" font URLs:
         //   https://www.google.com/fonts
         if ( details.type === 'object' ) {
-            if ( headerValue(details.responseHeaders, 'content-type').lastIndexOf('font/', 0) === 0 ) {
+            if ( headerValue(details.responseHeaders, 'content-type').startsWith('font/') ) {
                 details.type = 'font';
                 var r = onBeforeRequestClient(details);
                 if ( typeof r === 'object' && r.cancel === true ) {

platform/firefox/vapi-background.js

@@ -2361,7 +2361,7 @@ vAPI.net.registerListeners = function() {
         var tabId = tabWatcher.tabIdFromTarget(browser);
 
         // Ignore notifications related to our popup
-        if ( details.url.lastIndexOf(vAPI.getURL('popup.html'), 0) === 0 ) {
+        if ( details.url.startsWith(vAPI.getURL('popup.html')) ) {
             return;
         }
 

src/background.html

@@ -8,6 +8,7 @@
 <script src="lib/punycode.js"></script>
 <script src="lib/publicsuffixlist.js"></script>
 <script src="lib/yamd5.js"></script>
+<script src="js/polyfill.js"></script>
 <script src="js/vapi-common.js"></script>
 <script src="js/vapi-background.js"></script>
 <script src="js/background.js"></script>

src/js/assets.js

@@ -312,7 +312,7 @@ var getTextFileFromURL = function(url, onLoad, onError) {
         // appears to be a HTML document: could happen when server serves
         // some kind of error page I suppose
         var text = this.responseText.trim();
-        if ( text.charAt(0) === '<' && text.slice(-1) === '>' ) {
+        if ( text.startsWith('<') && text.endsWith('>') ) {
             return onError.call(this);
         }
         return onLoad.call(this);

src/js/cosmetic-filtering.js

@@ -191,7 +191,7 @@ var FilterHostname = function(s, hostname) {
 };
 
 FilterHostname.prototype.retrieve = function(hostname, out) {
-    if ( hostname.slice(-this.hostname.length) === this.hostname ) {
+    if ( hostname.endsWith(this.hostname) ) {
         out.push(this.s);
     }
 };
@@ -219,7 +219,7 @@ var FilterEntity = function(s, entity) {
 };
 
 FilterEntity.prototype.retrieve = function(entity, out) {
-    if ( entity.slice(-this.entity.length) === this.entity ) {
+    if ( entity.endsWith(this.entity) ) {
         out.push(this.s);
     }
 };
@@ -244,7 +244,6 @@ var FilterParser = function() {
     this.hostnames = [];
     this.invalid = false;
     this.cosmetic = true;
-    this.reScriptContains = /^script:contains\(.+?\)$/;
 };
 
 /******************************************************************************/
@@ -321,7 +320,7 @@ FilterParser.prototype.parse = function(raw) {
     // Cosmetic filters with explicit style properties can apply only:
     // - to specific cosmetic filters (those which apply to a specific site)
     // - to block cosmetic filters (not exception cosmetic filters)
-    if ( this.suffix.slice(-1) === '}' ) {
+    if ( this.suffix.endsWith('}') ) {
         // Not supported for now: this code will ensure some backward
         // compatibility for when cosmetic filters with explicit style
         // properties start to be in use.
@@ -341,7 +340,7 @@ FilterParser.prototype.parse = function(raw) {
     // Normalize high-medium selectors: `href` is assumed to imply `a` tag. We
     // need to do this here in order to correctly avoid duplicates. The test
     // is designed to minimize overhead -- this is a low occurrence filter.
-    if ( this.suffix.charAt(1) === '[' && this.suffix.slice(2, 9) === 'href^="' ) {
+    if ( this.suffix.startsWith('[href^="', 1) ) {
         this.suffix = this.suffix.slice(1);
     }
 
@@ -357,9 +356,9 @@ FilterParser.prototype.parse = function(raw) {
 
     // Inline script tag filter?
     if (
-        this.suffix.charAt(0) !== 's' ||
+        this.suffix.startsWith('script:contains(') === false ||
-        this.reScriptContains.test(this.suffix) === false )
+        this.suffix.endsWith(')') === false
-    {
+    ) {
         return this;
     }
 
@@ -370,17 +369,17 @@ FilterParser.prototype.parse = function(raw) {
         return this;
     }
 
-    var suffix = this.suffix;
+    var suffix = this.suffix.slice(16, -1);
     this.suffix = 'script//:';
 
     // Plain string-based?
-    if ( suffix.charAt(16) !== '/' || suffix.slice(-2) !== '/)' ) {
+    if ( suffix.startsWith('/') === false || suffix.endsWith('/') === false ) {
-        this.suffix += suffix.slice(16, -1).replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+        this.suffix += suffix.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
         return this;
     }
 
     // Regex-based
-    this.suffix += suffix.slice(17, -2).replace(/\\/g, '\\');
+    this.suffix += suffix.slice(1, -1);
 
     // Valid regex?
     if ( isBadRegex(this.suffix) ) {
@@ -687,7 +686,7 @@ FilterContainer.prototype.isValidSelector = (function() {
             return true;
         } catch (e) {
         }
-        if ( s.lastIndexOf('script//:', 0) === 0 ) {
+        if ( s.startsWith('script//:') ) {
             return true;
         }
         console.error('uBlock> invalid cosmetic filter:', s);
@@ -730,10 +729,10 @@ FilterContainer.prototype.compile = function(s, out) {
     var hostname;
     while ( i-- ) {
         hostname = hostnames[i];
-        if ( hostname.charAt(0) !== '~' ) {
+        if ( hostname.startsWith('~') === false ) {
             applyGlobally = false;
         }
-        if ( hostname.slice(-2) === '.*' ) {
+        if ( hostname.endsWith('.*') ) {
             this.compileEntitySelector(hostname, parsed, out);
         } else {
             this.compileHostnameSelector(hostname, parsed, out);
@@ -839,7 +838,7 @@ FilterContainer.prototype.reHighMedium = /^\[href\^="https?:\/\/([^"]{8})[^"]*"\
 FilterContainer.prototype.compileHostnameSelector = function(hostname, parsed, out) {
     // https://github.com/chrisaljoudi/uBlock/issues/145
     var unhide = parsed.unhide;
-    if ( hostname.charAt(0) === '~' ) {
+    if ( hostname.startsWith('~') ) {
         hostname = hostname.slice(1);
         unhide ^= 1;
     }
@@ -915,7 +914,7 @@ FilterContainer.prototype.fromCompiledContent = function(text, lineBeg, skip) {
         // h	ir	twitter.com	.promoted-tweet
         if ( fields[0] === 'h' ) {
             // Special filter: script tags. Not a real CSS selector.
-            if ( fields[3].lastIndexOf('script//:', 0) === 0 ) {
+            if ( fields[3].startsWith('script//:') ) {
                 this.createScriptTagFilter(fields[2], fields[3].slice(9));
                 continue;
             }
@@ -951,7 +950,7 @@ FilterContainer.prototype.fromCompiledContent = function(text, lineBeg, skip) {
         // entity	selector
         if ( fields[0] === 'e' ) {
             // Special filter: script tags. Not a real CSS selector.
-            if ( fields[2].lastIndexOf('script//:', 0) === 0 ) {
+            if ( fields[2].startsWith('script//:') ) {
                 this.createScriptTagFilter(fields[1], fields[2].slice(9));
                 continue;
             }
@@ -1224,16 +1223,17 @@ FilterContainer.prototype.addToSelectorCache = function(details) {
 /******************************************************************************/
 
 FilterContainer.prototype.removeFromSelectorCache = function(targetHostname, type) {
+    var targetHostnameLength = targetHostname.length;
     for ( var hostname in this.selectorCache ) {
         if ( this.selectorCache.hasOwnProperty(hostname) === false ) {
             continue;
         }
         if ( targetHostname !== '*' ) {
-            if ( hostname.slice(0 - targetHostname.length) !== targetHostname ) {
+            if ( hostname.endsWith(targetHostname) === false ) {
                 continue;
             }
-            if ( hostname.length !== targetHostname.length &&
+            if ( hostname.length !== targetHostnameLength &&
-                 hostname.charAt(0 - targetHostname.length - 1) !== '.' ) {
+                 hostname.charAt(hostname.length - targetHostnameLength - 1) !== '.' ) {
                 continue;
             }
         }

src/js/dynamic-net-filtering.js

@@ -89,7 +89,7 @@ var isIPAddress = function(hostname) {
     if ( reIPv4VeryCoarse.test(hostname) ) {
         return true;
     }
-    return hostname.charAt(0) === '[';
+    return hostname.startsWith('[');
 };
 
 /******************************************************************************/
@@ -325,7 +325,7 @@ var is3rdParty = function(srcHostname, desHostname) {
     // etc.
     var srcDomain = domainFromHostname(srcHostname) || srcHostname;
 
-    if ( desHostname.slice(0 - srcDomain.length) !== srcDomain ) {
+    if ( desHostname.endsWith(srcDomain) === false ) {
         return true;
     }
     // Do not confuse 'example.com' with 'anotherexample.com'
@@ -548,7 +548,7 @@ Matrix.prototype.fromString = function(text, append) {
 
         // Ignore special rules:
         //   hostname-based switch rules
-        if ( fields[0].slice(-1) === ':' ) {
+        if ( fields[0].endsWith(':') ) {
             continue;
         }
 

src/js/hnswitches.js

@@ -80,7 +80,7 @@ var isIPAddress = function(hostname) {
     if ( reIPv4VeryCoarse.test(hostname) ) {
         return true;
     }
-    return hostname.charAt(0) === '[';
+    return hostname.startsWith('[');
 };
 
 /******************************************************************************/
@@ -177,7 +177,7 @@ HnSwitches.prototype.toggleBranchZ = function(switchName, targetHostname, newSta
         if ( hostname.length <= targetLen ) {
             continue;
         }
-        if ( hostname.slice(-targetLen) !== targetHostname ) {
+        if ( hostname.endsWith(targetHostname) === false ) {
             continue;
         }
         if ( hostname.charAt(hostname.length - targetLen - 1) !== '.' ) {

src/js/logger-ui-inspector.js

@@ -32,7 +32,7 @@
 var showdomButton = uDom.nodeFromId('showdom');
 
 // Don't bother if the browser is not modern enough.
-if ( typeof Map === undefined || typeof WeakMap === undefined ) {
+if ( typeof Map === undefined || Map.polyfill || typeof WeakMap === undefined ) {
     showdomButton.classList.add('disabled');
     return;
 }

src/js/messaging.js

@@ -1287,7 +1287,7 @@ var onMessage = function(request, sender, callback) {
             if ( pageStore === null ) {
                 continue;
             }
-            if ( pageStore.rawURL.lastIndexOf(loggerURL, 0) === 0 ) {
+            if ( pageStore.rawURL.startsWith(loggerURL) ) {
                 continue;
             }
             tabIds[tabId] = pageStore.title;

src/js/polyfill.js

@@ -0,0 +1,146 @@
+/*******************************************************************************
+
+    uBlock Origin - a browser extension to block requests.
+    Copyright (C) 2015 Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+/******************************************************************************/
+
+(function() {
+
+'use strict';
+
+/******************************************************************************/
+
+// https://github.com/gorhill/uBlock/issues/1067
+// https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/startsWith
+// Firefox 17/Chromium 41 supports `startsWith`.
+
+if ( String.prototype.startsWith instanceof Function === false ) {
+    String.prototype.startsWith = function(needle, pos) {
+        if ( typeof pos !== 'number' ) {
+            pos = 0;
+        }
+        return this.lastIndexOf(needle, pos) === pos;
+    };
+}
+
+// https://github.com/gorhill/uBlock/issues/1067
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/endsWith
+// Firefox 17/Chromium 41 supports `endsWith`.
+
+if ( String.prototype.endsWith instanceof Function === false ) {
+    String.prototype.endsWith = function(needle, pos) {
+        if ( typeof pos !== 'number' ) {
+            pos = this.length;
+        }
+        pos -= needle.length;
+        return this.indexOf(needle, pos) === pos;
+    };
+}
+
+/******************************************************************************/
+
+// https://github.com/gorhill/uBlock/issues/1070
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set#Browser_compatibility
+// This polyfill is designed to fulfill *only* what uBlock Origin needs -- this
+// is not an accurate API of the real Set() type.
+
+if ( typeof self.Set !== 'function' ) {
+    self.Set = function() {
+        this.clear();
+    };
+
+    self.Set.polyfill = true;
+
+    self.Set.prototype.clear = function() {
+        this._set = Object.create(null);
+        this.size = 0;
+    };
+
+    self.Set.prototype.add = function(k) {
+        if ( this._set[k] === undefined ) {
+            this._set[k] = true;
+            this.size += 1;
+        }
+    };
+
+    self.Set.prototype.delete = function(k) {
+        if ( this._set[k] !== undefined ) {
+            delete this._set[k];
+            this.size -= 1;
+        }
+    };
+
+    self.Set.prototype.has = function(k) {
+        return this._set[k] !== undefined;
+    };
+}
+
+/******************************************************************************/
+
+// https://github.com/gorhill/uBlock/issues/1070
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set#Browser_compatibility
+// This polyfill is designed to fulfill *only* what uBlock Origin needs -- this
+// is not an accurate API of the real Map() type.
+
+if ( typeof self.Map !== 'function' ) {
+    self.Map = function() {
+        this.clear();
+    };
+
+    self.Map.polyfill = true;
+
+    self.Map.prototype.clear = function() {
+        this._map = Object.create(null);
+        this.size = 0;
+    };
+
+    self.Map.prototype.delete = function(k) {
+        if ( this._map[k] !== undefined ) {
+            delete this._map[k];
+            this.size -= 1;
+        }
+    };
+
+    self.Map.prototype.get = function(k) {
+        return this._map[k];
+    };
+
+    self.Set.prototype.has = function(k) {
+        return this._map[k] !== undefined;
+    };
+
+    self.Map.prototype.set = function(k, v) {
+        if ( v !== undefined ) {
+            if ( this._map[k] === undefined ) {
+                this.size += 1;
+            }
+            this._map[k] = v;
+        } else {
+            if ( this._map[k] !== undefined ) {
+                this.size -= 1;
+            }
+            delete this._map[k];
+        }
+    };
+}
+
+/******************************************************************************/
+
+})();

src/js/redirect-engine.js

@@ -227,11 +227,11 @@ RedirectEngine.prototype.compileRuleFromStaticFilter = function(line) {
     var srcs = [];
     var options = matches[3].split(','), option;
     while ( (option = options.pop()) ) {
-        if ( option.lastIndexOf('redirect=', 0) === 0 ) {
+        if ( option.startsWith('redirect=') ) {
             redirect = option.slice(9);
             continue;
         }
-        if ( option.lastIndexOf('domain=', 0) === 0 ) {
+        if ( option.startsWith('domain=') ) {
             srcs = option.slice(7).split('|');
             continue;
         }
@@ -251,7 +251,7 @@ RedirectEngine.prototype.compileRuleFromStaticFilter = function(line) {
     }
 
     // Need one single type -- not negated.
-    if ( type === undefined || type.charAt(0) === '~' ) {
+    if ( type === undefined || type.startsWith('~') ) {
         return;
     }
 
@@ -270,7 +270,7 @@ RedirectEngine.prototype.compileRuleFromStaticFilter = function(line) {
         if ( src === '' ) {
             continue;
         }
-        if ( src.charAt(0) === '~' ) {
+        if ( src.startsWith('~') ) {
             continue;
         }
         // Need at least one specific src or des.
@@ -376,7 +376,7 @@ RedirectEngine.prototype.resourcesFromString = function(text) {
         line = text.slice(lineBeg, lineEnd);
         lineBeg = lineEnd + 1;
 
-        if ( line.charAt(0) === '#' ) {
+        if ( line.startsWith('#') ) {
             continue;
         }
 

src/js/reverselookup-worker.js

@@ -99,7 +99,7 @@ var fromNetFilter = function(details) {
 
 var fromCosmeticFilter = function(details) {
     var filter = details.rawFilter;
-    var exception = filter.lastIndexOf('#@#', 0) === 0;
+    var exception = filter.startsWith('#@#');
 
     filter = exception ? filter.slice(3) : filter.slice(2);
 

src/js/static-net-filtering.js

@@ -168,13 +168,11 @@ var atoi = function(s) {
     return cachedParseInt(s, 10);
 };
 
-var isFirstParty = function(firstPartyDomain, hostname) {
+var isFirstParty = function(domain, hostname) {
-    if ( hostname.slice(0 - firstPartyDomain.length) !== firstPartyDomain ) {
-        return false;
-    }
     // Be sure to not confuse 'example.com' with 'anotherexample.com'
-    var c = hostname.charAt(hostname.length - firstPartyDomain.length - 1);
+    return hostname.endsWith(domain) &&
-    return c === '.' || c === '';
+          (hostname.length === domain.length ||
+           hostname.charAt(hostname.length - domain.length - 1) === '.');
 };
 
 var isBadRegex = function(s) {
@@ -235,26 +233,25 @@ var hostnameTestPicker = function(owner) {
 
     // Only one hostname
     if ( domainOpt.indexOf('|') === -1 ) {
-        return domainOpt.charAt(0) !== '~' ? hostnameHitTest : hostnameMissTest;
+        return domainOpt.startsWith('~') ? hostnameMissTest : hostnameHitTest;
     }
 
     // Multiple hostnames: use a dictionary.
-    var dict = owner._hostnameDict = Object.create(null);
     var hostnames = domainOpt.split('|');
-    var i, hostname;
+    var i, hostname, dict;
 
     // First find out whether we have a homogeneous dictionary
     var hit = false, miss = false;
     i = hostnames.length;
     while ( i-- ) {
-        if ( hostnames[i].charAt(0) !== '~' ) {
+        if ( hostnames[i].startsWith('~') ) {
-            hit = true;
+            miss = true;
-            if ( miss ) {
+            if ( hit ) {
                 break;
             }
         } else {
-            miss = true;
+            hit = true;
-            if ( hit ) {
+            if ( miss ) {
                 break;
             }
         }
@@ -264,40 +261,44 @@ var hostnameTestPicker = function(owner) {
     // Spotted one occurrence in EasyList Lite (cjxlist.txt):
     //   domain=photobucket.com|~secure.photobucket.com
     if ( hit && miss ) {
+        dict = owner._hostnameDict = new Map();
         i = hostnames.length;
         while ( i-- ) {
             hostname = hostnames[i];
-            if ( hostname.charAt(0) !== '~' ) {
+            if ( hostname.startsWith('~') ) {
-                dict[hostname] = true;
+                dict.set(hostname.slice(1), false);
             } else {
-                dict[hostname.slice(1)] = false;
+                dict.set(hostname, true);
             }
         }
         return hostnameMixedSetTest;
     }
 
     // Homogeneous dictionary.
+    dict = owner._hostnameDict = new Set();
     i = hostnames.length;
     while ( i-- ) {
         hostname = hostnames[i];
-        if ( hostname.charAt(0) !== '~' ) {
+        dict.add(hostname.startsWith('~') ? hostname.slice(1) : hostname);
-            dict[hostname] = true;
-        } else {
-            dict[hostname.slice(1)] = true;
-        }
     }
 
     return hit ? hostnameHitSetTest : hostnameMissSetTest;
 };
 
 var hostnameHitTest = function(owner) {
-    var hostname = owner.domainOpt;
+    var current = pageHostnameRegister;
-    return pageHostnameRegister.slice(0 - hostname.length) === hostname;
+    var target = owner.domainOpt;
+    return current.endsWith(target) &&
+          (current.length === target.length ||
+           current.charAt(current.length - target.length - 1) === '.');
 };
 
 var hostnameMissTest = function(owner) {
-    var hostname = owner.domainOpt;
+    var current = pageHostnameRegister;
-    return pageHostnameRegister.slice(1 - hostname.length) !== hostname.slice(1);
+    var target = owner.domainOpt;
+    return current.endsWith(target) === false ||
+          (current.length !== target.length &&
+           current.charAt(current.length - target.length - 1) !== '.');
 };
 
 var hostnameHitSetTest = function(owner) {
@@ -305,7 +306,7 @@ var hostnameHitSetTest = function(owner) {
     var needle = pageHostnameRegister;
     var pos;
     for (;;) {
-        if ( dict[needle] ) {
+        if ( dict.has(needle) ) {
             return true;
         }
         pos = needle.indexOf('.');
@@ -322,7 +323,7 @@ var hostnameMissSetTest = function(owner) {
     var needle = pageHostnameRegister;
     var pos;
     for (;;) {
-        if ( dict[needle] ) {
+        if ( dict.has(needle) ) {
             return false;
         }
         pos = needle.indexOf('.');
@@ -341,11 +342,11 @@ var hostnameMixedSetTest = function(owner) {
     var hit = false;
     var v, pos;
     for (;;) {
-        v = dict[needle] || undefined;
+        v = dict.get(needle);
         if ( v === false ) {
             return false;
         }
-        if ( v /* === true */ ) {
+        if ( v === true ) {
             hit = true;
         }
         pos = needle.indexOf('.');
@@ -393,7 +394,7 @@ var FilterPlain = function(s, tokenBeg) {
 };
 
 FilterPlain.prototype.match = function(url, tokenBeg) {
-    return url.substr(tokenBeg - this.tokenBeg, this.s.length) === this.s;
+    return url.startsWith(this.s, tokenBeg - this.tokenBeg);
 };
 
 FilterPlain.fid =
@@ -424,8 +425,8 @@ var FilterPlainHostname = function(s, tokenBeg, domainOpt) {
 };
 
 FilterPlainHostname.prototype.match = function(url, tokenBeg) {
-    return this.hostnameTest(this) &&
+    return url.startsWith(this.s, tokenBeg - this.tokenBeg) &&
-           url.substr(tokenBeg - this.tokenBeg, this.s.length) === this.s;
+           this.hostnameTest(this);
 };
 
 FilterPlainHostname.fid =
@@ -453,7 +454,7 @@ var FilterPlainPrefix0 = function(s) {
 };
 
 FilterPlainPrefix0.prototype.match = function(url, tokenBeg) {
-    return url.substr(tokenBeg, this.s.length) === this.s;
+    return url.startsWith(this.s, tokenBeg);
 };
 
 FilterPlainPrefix0.fid =
@@ -482,8 +483,8 @@ var FilterPlainPrefix0Hostname = function(s, domainOpt) {
 };
 
 FilterPlainPrefix0Hostname.prototype.match = function(url, tokenBeg) {
-    return this.hostnameTest(this) &&
+    return url.startsWith(this.s, tokenBeg) &&
-           url.substr(tokenBeg, this.s.length) === this.s;
+           this.hostnameTest(this);
 };
 
 FilterPlainPrefix0Hostname.fid =
@@ -511,7 +512,7 @@ var FilterPlainPrefix1 = function(s) {
 };
 
 FilterPlainPrefix1.prototype.match = function(url, tokenBeg) {
-    return url.substr(tokenBeg - 1, this.s.length) === this.s;
+    return url.startsWith(this.s, tokenBeg - 1);
 };
 
 FilterPlainPrefix1.fid =
@@ -540,8 +541,8 @@ var FilterPlainPrefix1Hostname = function(s, domainOpt) {
 };
 
 FilterPlainPrefix1Hostname.prototype.match = function(url, tokenBeg) {
-    return this.hostnameTest(this) &&
+    return url.startsWith(this.s, tokenBeg - 1) &&
-           url.substr(tokenBeg - 1, this.s.length) === this.s;
+           this.hostnameTest(this);
 };
 
 FilterPlainPrefix1Hostname.fid =
@@ -569,7 +570,7 @@ var FilterPlainLeftAnchored = function(s) {
 };
 
 FilterPlainLeftAnchored.prototype.match = function(url) {
-    return url.slice(0, this.s.length) === this.s;
+    return url.startsWith(this.s);
 };
 
 FilterPlainLeftAnchored.fid =
@@ -598,8 +599,8 @@ var FilterPlainLeftAnchoredHostname = function(s, domainOpt) {
 };
 
 FilterPlainLeftAnchoredHostname.prototype.match = function(url) {
-    return this.hostnameTest(this) &&
+    return url.startsWith(this.s) &&
-           url.slice(0, this.s.length) === this.s;
+           this.hostnameTest(this);
 };
 
 FilterPlainLeftAnchoredHostname.fid =
@@ -627,7 +628,7 @@ var FilterPlainRightAnchored = function(s) {
 };
 
 FilterPlainRightAnchored.prototype.match = function(url) {
-    return url.slice(-this.s.length) === this.s;
+    return url.endsWith(this.s);
 };
 
 FilterPlainRightAnchored.fid =
@@ -656,8 +657,8 @@ var FilterPlainRightAnchoredHostname = function(s, domainOpt) {
 };
 
 FilterPlainRightAnchoredHostname.prototype.match = function(url) {
-    return this.hostnameTest(this) &&
+    return url.endsWith(this.s) &&
-           url.slice(-this.s.length) === this.s;
+           this.hostnameTest(this);
 };
 
 FilterPlainRightAnchoredHostname.fid =
@@ -688,7 +689,7 @@ var FilterPlainHnAnchored = function(s) {
 };
 
 FilterPlainHnAnchored.prototype.match = function(url, tokenBeg) {
-    if ( url.substr(tokenBeg, this.s.length) !== this.s ) {
+    if ( url.startsWith(this.s, tokenBeg) === false ) {
         return false;
     }
     // Valid only if hostname-valid characters to the left of token
@@ -715,6 +716,7 @@ FilterPlainHnAnchored.fromSelfie = function(s) {
 };
 
 // https://www.youtube.com/watch?v=71YS6xDB-E4
+// https://www.youtube.com/watch?v=qBPML7ton0E
 
 /******************************************************************************/
 
@@ -727,10 +729,10 @@ var FilterPlainHnAnchoredHostname = function(s, domainOpt) {
 };
 
 FilterPlainHnAnchoredHostname.prototype.match = function(url, tokenBeg) {
-    if ( this.hostnameTest(this) === false ) {
+    if (
-        return false;
+        url.startsWith(this.s, tokenBeg) === false ||
-    }
+        this.hostnameTest(this) === false
-    if ( url.substr(tokenBeg, this.s.length) !== this.s ) {
+    ) {
         return false;
     }
     // Valid only if hostname-valid characters to the left of token
@@ -805,10 +807,8 @@ FilterGenericHostname.prototype = Object.create(FilterGeneric.prototype);
 FilterGenericHostname.prototype.constructor = FilterGenericHostname;
 
 FilterGenericHostname.prototype.match = function(url) {
-    if ( this.hostnameTest(this) === false ) {
+    return this.hostnameTest(this) &&
-        return false;
+           FilterGeneric.prototype.match.call(this, url);
-    }
-    return FilterGeneric.prototype.match.call(this, url);
 };
 
 FilterGenericHostname.fid =
@@ -884,10 +884,8 @@ FilterGenericHnAnchoredHostname.prototype = Object.create(FilterGenericHnAnchore
 FilterGenericHnAnchoredHostname.prototype.constructor = FilterGenericHnAnchoredHostname;
 
 FilterGenericHnAnchoredHostname.prototype.match = function(url) {
-    if ( this.hostnameTest(this) === false ) {
+    return this.hostnameTest(this) &&
-        return false;
+           FilterGenericHnAnchored.prototype.match.call(this, url);
-    }
-    return FilterGenericHnAnchored.prototype.match.call(this, url);
 };
 
 FilterGenericHnAnchoredHostname.fid =
@@ -1004,7 +1002,7 @@ FilterHostnameDict.prototype.cutoff = 250;
 
 FilterHostnameDict.prototype.meltBucket = function(len, bucket) {
     var map = {};
-    if ( bucket.charAt(0) === ' ' ) {
+    if ( bucket.startsWith(' ') ) {
         bucket.trim().split(' ').map(function(k) {
             map[k] = true;
         });
@@ -1105,7 +1103,7 @@ FilterHostnameDict.prototype.matchesExactly = function(hn) {
     if ( typeof bucket === 'object' ) {
         bucket = this.dict[key] = this.freezeBucket(bucket);
     }
-    if ( bucket.charAt(0) === ' ' ) {
+    if ( bucket.startsWith(' ') ) {
         return bucket.indexOf(' ' + hn + ' ') !== -1;
     }
     // binary search
@@ -1379,7 +1377,7 @@ FilterParser.prototype.parseOptions = function(s) {
     var opt, not;
     for ( var i = 0; i < opts.length; i++ ) {
         opt = opts[i];
-        not = opt.charAt(0) === '~';
+        not = opt.startsWith('~');
         if ( not ) {
             opt = opt.slice(1);
         }
@@ -1411,7 +1409,7 @@ FilterParser.prototype.parseOptions = function(s) {
             this.parseOptType(opt, not);
             continue;
         }
-        if ( opt.lastIndexOf('domain=', 0) === 0 ) {
+        if ( opt.startsWith('domain=') ) {
             this.domainOpt = opt.slice(7);
             continue;
         }
@@ -1423,7 +1421,7 @@ FilterParser.prototype.parseOptions = function(s) {
             this.parseOptParty(true, not);
             continue;
         }
-        if ( opt.lastIndexOf('redirect=', 0) === 0 ) {
+        if ( opt.startsWith('redirect=') ) {
             if ( this.action === BlockAction ) {
                 this.redirect = true;
                 continue;
@@ -1466,7 +1464,7 @@ FilterParser.prototype.parse = function(raw) {
 
     // block or allow filter?
     // Important: this must be executed before parsing options
-    if ( s.lastIndexOf('@@', 0) === 0 ) {
+    if ( s.startsWith('@@') ) {
         this.action = AllowAction;
         s = s.slice(2);
     }
@@ -1475,7 +1473,7 @@ FilterParser.prototype.parse = function(raw) {
     // https://github.com/gorhill/uBlock/issues/842
     // - ensure sure we are not dealing with a regex-based filter.
     // - lookup the last occurrence of `$`.
-    if ( s.charAt(0) !== '/' || s.slice(-1) !== '/' ) {
+    if ( s.startsWith('/') === false || s.endsWith('/') === false ) {
         pos = s.lastIndexOf('$');
         if ( pos !== -1 ) {
             // https://github.com/gorhill/uBlock/issues/952
@@ -1490,7 +1488,7 @@ FilterParser.prototype.parse = function(raw) {
     }
 
     // regex?
-    if ( s.charAt(0) === '/' && s.slice(-1) === '/' && s.length > 2 ) {
+    if ( s.startsWith('/') && s.endsWith('/') && s.length > 2 ) {
         this.isRegex = true;
         this.f = s.slice(1, -1);
         if ( isBadRegex(this.f) ) {
@@ -1505,7 +1503,7 @@ FilterParser.prototype.parse = function(raw) {
     }
 
     // hostname-anchored
-    if ( s.lastIndexOf('||', 0) === 0 ) {
+    if ( s.startsWith('||') ) {
         this.hostnameAnchored = true;
         s = s.slice(2);
 
@@ -1519,7 +1517,7 @@ FilterParser.prototype.parse = function(raw) {
         }
 
         // https://github.com/chrisaljoudi/uBlock/issues/1096
-        if ( s.charAt(0) === '^' ) {
+        if ( s.startsWith('^') ) {
             this.unsupported = true;
             return this;
         }
@@ -1533,13 +1531,13 @@ FilterParser.prototype.parse = function(raw) {
     }
 
     // left-anchored
-    if ( s.charAt(0) === '|' ) {
+    if ( s.startsWith('|') ) {
         this.anchor = -1;
         s = s.slice(1);
     }
 
     // right-anchored
-    if ( s.slice(-1) === '|' ) {
+    if ( s.endsWith('|') ) {
         this.anchor = 1;
         s = s.slice(0, -1);
     }
@@ -1547,11 +1545,11 @@ FilterParser.prototype.parse = function(raw) {
     // normalize placeholders
     if ( this.reHasWildcard.test(s) ) {
         // remove pointless leading *
-        if ( s.charAt(0) === '*' ) {
+        if ( s.startsWith('*') ) {
             s = s.replace(/^\*+([^%0-9a-z])/, '$1');
         }
         // remove pointless trailing *
-        if ( s.slice(-1) === '*' ) {
+        if ( s.endsWith('*') ) {
             s = s.replace(/([^%0-9a-z])\*+$/, '$1');
         }
     }

src/js/storage.js

@@ -125,7 +125,7 @@
             // https://github.com/gorhill/uBlock/issues/277
             // uBlock's filter lists are always enabled by default, so we
             // have to include in backup only those which are turned off.
-            if ( path.lastIndexOf('assets/ublock/', 0) === 0 ) {
+            if ( path.startsWith('assets/ublock/') ) {
                 if ( entry.off !== true ) {
                     delete result[path];
                 }

src/js/tab.js

@@ -453,7 +453,7 @@ vAPI.tabs.onNavigation = function(details) {
     // TODO: Eventually, we will have to use an API to check whether a scheme
     //       is supported as I suspect we are going to start to see `ws`, `wss`
     //       as well soon.
-    if ( pageStore && tabContext.rawURL.lastIndexOf('http', 0) === 0 ) {
+    if ( pageStore && tabContext.rawURL.startsWith('http') ) {
         pageStore.hostnameToCountMap[tabContext.rootHostname] = 0;
     }
 };
@@ -618,7 +618,7 @@ vAPI.tabs.onPopupUpdated = (function() {
 
         // If the page URL is that of our "blocked page" URL, extract the URL of
         // the page which was blocked.
-        if ( targetURL.lastIndexOf(vAPI.getURL('document-blocked.html'), 0) === 0 ) {
+        if ( targetURL.startsWith(vAPI.getURL('document-blocked.html')) ) {
             var matches = /details=([^&]+)/.exec(targetURL);
             if ( matches !== null ) {
                 targetURL = JSON.parse(atob(matches[1])).url;

src/js/ublock.js

@@ -47,7 +47,9 @@ var isHandcraftedWhitelistDirective = function(directive) {
 var matchWhitelistDirective = function(url, hostname, directive) {
     // Directive is a plain hostname
     if ( directive.indexOf('/') === -1 ) {
-        return hostname.slice(-directive.length) === directive;
+        return hostname.endsWith(directive) &&
+              (hostname.length === directive.length ||
+               hostname.charAt(hostname.length - directive.length - 1) === '.');
     }
     // Match URL exactly
     if ( directive.indexOf('*') === -1 ) {
@@ -187,7 +189,7 @@ var matchWhitelistDirective = function(url, hostname, directive) {
         }
 
         // Don't throw out commented out lines: user might want to fix them
-        if ( line.charAt(0) === '#' ) {
+        if ( line.startsWith('#') ) {
             key = '#';
             directive = line;
         }

src/js/uritools.js

@@ -179,7 +179,7 @@ URI.set = function(uri) {
     }
     this.hostname = matches[1] !== undefined ? matches[1] : '';
     // http://en.wikipedia.org/wiki/FQDN
-    if ( this.hostname.slice(-1) === '.' ) {
+    if ( this.hostname.endsWith('.') ) {
         this.hostname = this.hostname.slice(0, -1);
     }
     this.port = matches[2] !== undefined ? matches[2].slice(1) : '';
@@ -271,7 +271,7 @@ URI.hostnameFromURI = function(uri) {
     }
     // http://en.wikipedia.org/wiki/FQDN
     var hostname = matches[1];
-    if ( hostname.slice(-1) === '.' ) {
+    if ( hostname.endsWith('.') ) {
         hostname = hostname.slice(0, -1);
     }
     return hostname.toLowerCase();

src/js/url-net-filtering.js

@@ -92,7 +92,7 @@ var indexOfMatch = function(urls, url) {
         if ( entry.url.length > urlLen ) {
             continue;
         }
-        if ( url.lastIndexOf(entry.url, 0) === 0 ) {
+        if ( url.startsWith(entry.url) ) {
             return i;
         }
     }