Settle stupid naming dispute.

common/content/bookmarks.js

@@ -188,7 +188,7 @@ const Bookmarks = Module("bookmarks", {
      * @returns {nsISearchEngine} The search engine.
      */
     getSearchEngine: function getSearchEngine(alias)
-        this.searchEngines.filter(function (e) e.keyword === alias)[0],
+        array.nth(this.searchEngines, function (e) e.keyword === alias, 0),
 
     getSearchEngines: deprecated("Please use bookmarks.searchEngines instead", function getSearchEngines() this.searchEngines),
     /**

common/content/commands.js

@@ -614,9 +614,8 @@ const Commands = Module("commands", {
      *     any of the command's names.
      * @returns {Command}
      */
-    get: function (name, full) {
-        return this._exMap[name] || !full && this._exCommands.filter(function (cmd) cmd.hasName(name))[0] || null;
-    },
+    get: function (name, full)
+        this._exMap[name] || !full && array.nth(this._exCommands, function (cmd) cmd.hasName(name), 0) || null,
 
     /**
      * Returns the user-defined command with matching *name*.
@@ -625,9 +624,8 @@ const Commands = Module("commands", {
      *     any of the command's names.
      * @returns {Command}
      */
-    getUserCommand: function (name) {
-        return this._exCommands.filter(function (cmd) cmd.user && cmd.hasName(name))[0] || null;
-    },
+    getUserCommand: function (name)
+        array.nth(this._exCommands, function (cmd) cmd.user && cmd.hasName(name), 0) || null,
 
     /**
      * Returns all user-defined commands.

common/content/tabs.js

@@ -432,7 +432,7 @@ const Tabs = Module("tabs", {
         if (matches)
             return tabs.select(this.allTabs[parseInt(matches[1], 10) - 1], false);
 
-        matches = array.first(tabs.allTabs, function (t) t.linkedBrowser.lastURI.spec === buffer);
+        matches = array.nth(tabs.allTabs, function (t) t.linkedBrowser.lastURI.spec === buffer, 0);
         if (matches)
             return tabs.select(matches, false);
 

common/modules/base.jsm

@@ -1071,17 +1071,6 @@ const array = Class("array", Array, {
     equals: function (ary1, ary2)
         ary1.length === ary2.length && Array.every(ary1, function (e, i) e === ary2[i]),
 
-    /**
-     * Returns the first member of the given array that matches the
-     * given predicate.
-     */
-    first: function first(ary, pred, self) {
-        for (let elem in values(ary))
-            if (pred.call(self, elem))
-                return elem;
-        return undefined;
-    },
-
     /**
      * Flattens an array, such that all elements of the array are
      * joined into a single array:
@@ -1116,6 +1105,17 @@ const array = Class("array", Array, {
             yield [i, ary[i]];
     },
 
+    /**
+     * Returns the nth member of the given array that matches the
+     * given predicate.
+     */
+    nth: function first(ary, pred, n, self) {
+        for (let elem in values(ary))
+            if (pred.call(self, elem) && n-- === 0)
+                return elem;
+        return undefined;
+    },
+
     /**
      * Filters out all duplicates from an array. If *unsorted* is false, the
      * array is sorted before duplicates are removed.

common/modules/sanitizer.jsm

@@ -624,8 +624,7 @@ const Sanitizer = Module("sanitizer", XPCOM([Ci.nsIObserver, Ci.nsISupportsWeakR
                     ["prompt",  "Always prompt for a lifetime"],
                     ["session", "The current session"]
                 ],
-                getter: function () (this.completer()[prefs.get(this.PREF)]
-                        || [prefs.get(this.PREF_DAYS)])[0],
+                getter: function () (this.completer()[prefs.get(this.PREF)] || [prefs.get(this.PREF_DAYS)])[0],
                 setter: function (value) {
                     let val = this.completer().map(function (i) i[0]).indexOf(value);
                     if (val > -1)