Improve escapes with a bs.js library

I resisted this, but it makes BS more useful, so what can you do?

BullScript.JSON-tmLanguage

@@ -8,7 +8,7 @@
         "0": { "name": "string.quoted.double.js" }
       },
       "patterns": [
-        { "begin": "#[nxX]?{",
+        { "begin": "#[nNxX]?{",
           "end": "}",
           "patterns": [
             { "include": "$self" }
@@ -28,7 +28,7 @@
         "1": { "name": "entity.name.tag.html" }
       },
       "patterns": [
-        { "begin": "#[nxX]?{",
+        { "begin": "#[nNxX]?{",
           "end": "}",
           "patterns": [
             { "include": "$self" }

bs.js

@@ -0,0 +1,26 @@
+(function() {
+    bs = {
+        x: function(y) {
+            if (y === null || y === undefined)
+                return '';
+            return encodeURIComponent(y).replace('%20', '+');
+        },
+        X: function(y) {
+            if (y === null || y === undefined)
+                return '';
+            return encodeURIComponent(y).replace(/[!'()]/g, escape).replace(/\*/g, '%2A');
+        },
+        n: function(y) {
+            if (y === null || y === undefined)
+                return '';
+            return y;
+        },
+        N: function(y) {
+            if (y instanceof Array && y.length <= 0)
+                return '';
+            if (y instanceof Object && Object.keys(y).length <= 0)
+                return '';
+            return y || '';
+        }
+    };
+})();

bsc

@@ -141,16 +141,11 @@ end
 
 class String
   def bsubst sep = '"'
-    self.gsub(/#([nxX]?)\{(.*?)\}/) do
-      inner = case $1
-      when 'n'
-        "((#{$2}) || '')"
-      when 'X'
-        "encodeURIComponent(#{$2}).replace(/[!'()]/g, escape).replace(/\\*/g, '%2A')"
-      when 'x'
-        "encodeURIComponent(#{$2}).replace('%20', '+')"
+    self.gsub(/#([nNxX]?)\{(.*?)\}/) do
+      inner = if $1 and $1.length > 0
+        "bs.#$1(#$2)"
       else
-        "(#{$2})"
+        "(#$2)"
       end
       %Q{#{sep} + #{inner} + #{sep}}
     end

tests

@@ -62,11 +62,11 @@ class BullTests < Test::Unit::TestCase
   end
 
   def test_falsy_subst
-    assert_equal %q{"foo #n{bar} foo"}.to_js, %q{"foo " + ((bar) || '') + " foo"}
+    assert_equal %q{"foo #n{bar} foo"}.to_js, %q{"foo " + bs.n(bar) + " foo"}
   end
 
   def test_URI_encoded_subst
-    assert_equal %q{"foo #x{bar} foo"}.to_js, %q{"foo " + encodeURIComponent(bar).replace('%20', '+') + " foo"}
+    assert_equal %q{"foo #x{bar} foo"}.to_js, %q{"foo " + bs.x(bar) + " foo"}
   end
 
   def test_html1
@@ -197,15 +197,16 @@ class BullTests < Test::Unit::TestCase
 
   def test_multiline_with_internal_quotes
     input = <<-end.to_js
-    """foo
-    bar \#{jee || ''} haha
-    mooface
-    """
+      """foo
+      bar \#{jee || ''} haha
+      mooface
+      """
+    end
     output = <<-end.to_js
-    'foo\n'+
-    'bar ' + (jee || '') + ' haha\n'+
-    'mooface\n'+
-    ''
+      'foo\\n'+
+      'bar ' + (jee || '') + ' haha\\n'+
+      'mooface\\n'+
+      ''
     end
     assert_equal output, input
   end