Default arguments ftw.

common/content/statusline.js

@@ -377,10 +377,7 @@ var StatusLine = Module("statusline", {
      * @param {number} percent The zoom level, as a percentage. @optional
      * @param {boolean} full True if full zoom is in operation. @optional
      */
-    updateZoomLevel: function updateZoomLevel(percent, full) {
-        if (arguments.length == 0)
-            [percent, full] = [buffer.zoomLevel, buffer.fullZoom];
-
+    updateZoomLevel: function updateZoomLevel(percent=buffer.zoomLevel, full=buffer.fullZoom) {
         if (percent == 100)
             this.widgets.zoomlevel.value = "";
         else {

common/modules/commands.jsm

@@ -971,10 +971,7 @@ var Commands = Module("commands", {
     parseArgs: function parseArgs(str, params) {
         const self = this;
 
-        function getNextArg(str, _keepQuotes) {
-            if (arguments.length < 2)
-                _keepQuotes = keepQuotes;
-
+        function getNextArg(str, _keepQuotes=keepQuotes) {
             if (str.substr(0, 2) === "<<" && hereDoc) {
                 let arg = /^<<(\S*)/.exec(str)[1];
                 let count = arg.length + 2;

common/modules/contexts.jsm

@@ -65,10 +65,7 @@ var Group = Class("Group", {
     get builtin() this.modules.contexts.builtinGroups.indexOf(this) >= 0,
 
 }, {
-    compileFilter: function (patterns, default_ = false) {
-        if (arguments.length < 2)
-            default_ = false;
-
+    compileFilter: function (patterns, default_=false) {
         function siteFilter(uri)
             let (match = array.nth(siteFilter.filters, f => f(uri), 0))
                 match ? match.result : default_;

common/modules/dom.jsm

@@ -1090,12 +1090,10 @@ var DOM = Class("DOM", {
          * @param {string} keys Messy form.
          * @param {boolean} unknownOk Whether unknown keys are passed
          *     through rather than being converted to <lt>keyname>.
-         *     @default false
+         *     @default true
          * @returns {string} Canonical form.
          */
-        canonicalKeys: function canonicalKeys(keys, unknownOk) {
-            if (arguments.length === 1)
-                unknownOk = true;
+        canonicalKeys: function canonicalKeys(keys, unknownOk=true) {
             return this.parse(keys, unknownOk).map(this.closure.stringify).join("");
         },
 
@@ -1122,16 +1120,13 @@ var DOM = Class("DOM", {
          * @param {string} keys The string to parse.
          * @param {boolean} unknownOk Whether unknown keys are passed
          *     through rather than being converted to <lt>keyname>.
-         *     @default false
+         *     @default true
          * @returns {Array[Object]}
          */
-        parse: function parse(input, unknownOk) {
+        parse: function parse(input, unknownOk=true) {
             if (isArray(input))
                 return array.flatten(input.map(k => this.parse(k, unknownOk)));
 
-            if (arguments.length === 1)
-                unknownOk = true;
-
             let out = [];
             for (let match in util.regexp.iterate(/<.*?>?>|[^<]|<(?!.*>)/g, input)) {
                 let evt_str = match[0];

common/modules/finder.jsm

@@ -75,9 +75,7 @@ var RangeFinder = Module("rangefinder", {
         this.find("", mode == this.modes.FIND_BACKWARD);
     },
 
-    bootstrap: function bootstrap(str, backward) {
-        if (arguments.length < 2 && this.rangeFind)
-            backward = this.rangeFind.reverse;
+    bootstrap: function bootstrap(str, backward=this.rangeFind && this.rangeFind.reverse) {
 
         let highlighted = this.rangeFind && this.rangeFind.highlighted;
         let selections = this.rangeFind && this.rangeFind.selections;

common/modules/io.jsm

@@ -266,8 +266,8 @@ var IO = Module("io", {
      */
     File: Class.Memoize(function () let (io = this)
         Class("File", File, {
-            init: function init(path, checkCWD)
-                init.supercall(this, path, (arguments.length < 2 || checkCWD) && io.cwd)
+            init: function init(path, checkCWD=true)
+                init.supercall(this, path, checkCWD && io.cwd)
         })),
 
     /**

common/modules/options.jsm

@@ -480,11 +480,11 @@ var Option = Class("Option", {
         stringlist: function stringlist(k) this.value.indexOf(k) >= 0,
         get charlist() this.stringlist,
 
-        regexplist: function regexplist(k, default_) {
+        regexplist: function regexplist(k, default_=null) {
             for (let re in values(this.value))
                 if ((re.test || re).call(re, k))
                     return re.result;
-            return arguments.length > 1 ? default_ : null;
+            return default_;
         },
         get regexpmap() this.regexplist,
         get sitelist() this.regexplist,

common/modules/util.jsm

@@ -588,10 +588,10 @@ var Util = Module("Util", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakReference]),
      * @param {string} msg The trace message.
      * @param {number} frames The number of frames to print.
      */
-    dumpStack: function dumpStack(msg, frames) {
+    dumpStack: function dumpStack(msg="Stack", frames=null) {
         let stack = util.stackLines(Error().stack);
         stack = stack.slice(1, 1 + (frames || stack.length)).join("\n").replace(/^/gm, "    ");
-        util.dump((arguments.length == 0 ? "Stack" : msg) + "\n" + stack + "\n");
+        util.dump(msg + "\n" + stack + "\n");
     },
 
     /**