refactor: some minor performance improvements

dist/showdown.js

@@ -830,6 +830,14 @@ if (typeof(console) === 'undefined') {
     }
   };
 }
+
+/**
+ * Common regexes.
+ * We declare some common regexes to improve performance
+ */
+showdown.helper.regexes = {
+  asteriskAndDash: /([*_])/g
+};
 
 /**
  * Created by Estevao on 31-05-2015.
@@ -1297,12 +1305,15 @@ showdown.subParser('anchors', function (text, options, globals) {
       }
     }
 
-    url = showdown.helper.escapeCharacters(url, '*_', false);
+    //url = showdown.helper.escapeCharacters(url, '*_', false); // replaced line to improve performance
+    url = url.replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
+
     var result = '<a href="' + url + '"';
 
     if (title !== '' && title !== null) {
       title = title.replace(/"/g, '&quot;');
-      title = showdown.helper.escapeCharacters(title, '*_', false);
+      //title = showdown.helper.escapeCharacters(title, '*_', false); // replaced line to improve performance
+      title = title.replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
       result += ' title="' + title + '"';
     }
 
@@ -1636,14 +1647,15 @@ showdown.subParser('encodeCode', function (text) {
 
   // Encode all ampersands; HTML entities are not
   // entities within a Markdown code span.
-  text = text.replace(/&/g, '&amp;');
-
+  text = text
+    .replace(/&/g, '&amp;')
   // Do the angle bracket song and dance:
-  text = text.replace(/</g, '&lt;');
-  text = text.replace(/>/g, '&gt;');
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
 
   // Now, escape characters that are magic in Markdown:
-  text = showdown.helper.escapeCharacters(text, '*_{}[]\\', false);
+  //text = showdown.helper.escapeCharacters(text, '*_{}[]\\', false); // replaced line to improve performance
+    .replace(/([*_{}\[\]\\])/g, showdown.helper.escapeCharactersCallback);
 
   // jj the line above breaks this:
   //---
@@ -1667,9 +1679,10 @@ showdown.subParser('escapeSpecialCharsWithinTagAttributes', function (text) {
   var regex = /(<[a-z\/!$]("[^"]*"|'[^']*'|[^'">])*>|<!(--.*?--\s*)+>)/gi;
 
   text = text.replace(regex, function (wholeMatch) {
-    var tag = wholeMatch.replace(/(.)<\/?code>(?=.)/g, '$1`');
-    tag = showdown.helper.escapeCharacters(tag, '\\`*_', false);
-    return tag;
+    return wholeMatch
+      .replace(/(.)<\/?code>(?=.)/g, '$1`')
+    //tag = showdown.helper.escapeCharacters(tag, '\\`*_', false);
+      .replace(/([\\`*_])/g, showdown.helper.escapeCharactersCallback);
   });
 
   return text;
@@ -2014,14 +2027,19 @@ showdown.subParser('images', function (text, options, globals) {
       }
     }
 
-    altText = altText.replace(/"/g, '&quot;');
-    altText = showdown.helper.escapeCharacters(altText, '*_', false);
-    url = showdown.helper.escapeCharacters(url, '*_', false);
+    altText = altText
+      .replace(/"/g, '&quot;')
+    //altText = showdown.helper.escapeCharacters(altText, '*_', false);
+      .replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
+    //url = showdown.helper.escapeCharacters(url, '*_', false);
+    url = url.replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
     var result = '<img src="' + url + '" alt="' + altText + '"';
 
     if (title) {
-      title = title.replace(/"/g, '&quot;');
-      title = showdown.helper.escapeCharacters(title, '*_', false);
+      title = title
+        .replace(/"/g, '&quot;')
+      //title = showdown.helper.escapeCharacters(title, '*_', false);
+        .replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
       result += ' title="' + title + '"';
     }
 

performance.log.md

@@ -6,41 +6,41 @@
 ### Test Suite: Basic (50 cycles)
 | test | avgTime | max | min |
 |:-----|--------:|----:|----:|
-|Simple "Hello World"|0.330|5.345|0.168|
-|readme.md|25.823|46.558|23.516|
+|Simple "Hello World"|0.333|5.420|0.160|
+|readme.md|25.445|46.022|23.553|
 
 ### Test Suite: subParsers (20 cycles)
 | test | avgTime | max | min |
 |:-----|--------:|----:|----:|
-|hashHTMLBlocks|2.599|8.291|1.929|
-|anchors|0.519|4.014|0.272|
-|autoLinks|0.089|0.193|0.071|
-|blockQuotes|3.127|6.063|2.751|
-|codeBlocks|0.178|0.294|0.168|
-|codeSpans|0.233|0.569|0.178|
-|detab|0.129|0.796|0.087|
-|encodeAmpsAndAngles|0.042|0.076|0.037|
-|encodeBackslashEscapes|0.072|0.104|0.068|
-|encodeCode|0.529|0.826|0.484|
-|escapeSpecialCharsWithinTagAttributes|0.359|0.444|0.325|
-|githubCodeBlocks|0.189|0.776|0.141|
-|hashBlock|0.056|0.343|0.037|
-|hashElement|0.002|0.028|0.000|
-|hashHTMLSpans|0.599|3.072|0.248|
-|hashPreCodeTags|0.200|0.343|0.132|
-|headers|1.069|1.445|0.934|
-|horizontalRule|0.310|1.091|0.198|
-|images|0.192|0.310|0.116|
-|italicsAndBold|0.194|0.243|0.141|
-|lists|5.782|9.187|4.470|
-|outdent|0.158|0.226|0.141|
-|paragraphs|3.712|4.484|3.384|
-|spanGamut|1.586|2.240|1.380|
-|strikethrough|0.002|0.042|0.000|
-|stripBlankLines|0.089|0.119|0.083|
-|stripLinkDefinitions|0.170|0.279|0.143|
-|tables|0.003|0.036|0.000|
-|unescapeSpecialChars|0.008|0.038|0.006|
+|hashHTMLBlocks|2.565|8.039|1.909|
+|anchors|0.475|3.950|0.261|
+|autoLinks|0.099|0.218|0.072|
+|blockQuotes|3.265|5.968|2.812|
+|codeBlocks|0.170|0.325|0.149|
+|codeSpans|0.195|0.405|0.141|
+|detab|0.126|0.736|0.083|
+|encodeAmpsAndAngles|0.041|0.079|0.037|
+|encodeBackslashEscapes|0.077|0.140|0.069|
+|encodeCode|0.542|0.872|0.490|
+|escapeSpecialCharsWithinTagAttributes|0.258|0.584|0.217|
+|githubCodeBlocks|0.167|0.713|0.128|
+|hashBlock|0.062|0.462|0.037|
+|hashElement|0.002|0.039|0.000|
+|hashHTMLSpans|0.492|2.612|0.247|
+|hashPreCodeTags|0.125|0.275|0.102|
+|headers|0.783|0.912|0.722|
+|horizontalRule|0.207|0.303|0.196|
+|images|0.120|0.867|0.073|
+|italicsAndBold|0.098|0.138|0.089|
+|lists|4.962|5.655|4.556|
+|outdent|0.176|0.269|0.143|
+|paragraphs|3.587|4.459|3.142|
+|spanGamut|1.392|2.037|1.177|
+|strikethrough|0.006|0.110|0.000|
+|stripBlankLines|0.089|0.140|0.080|
+|stripLinkDefinitions|0.165|0.224|0.143|
+|tables|0.002|0.034|0.000|
+|unescapeSpecialChars|0.009|0.039|0.007|
 
 
 ## [version 1.6.0](https://github.com/showdownjs/showdown/tree/1.6.0)

src/helpers.js

@@ -333,3 +333,11 @@ if (typeof(console) === 'undefined') {
     }
   };
 }
+
+/**
+ * Common regexes.
+ * We declare some common regexes to improve performance
+ */
+showdown.helper.regexes = {
+  asteriskAndDash: /([*_])/g
+};

src/subParsers/anchors.js

@@ -38,12 +38,15 @@ showdown.subParser('anchors', function (text, options, globals) {
       }
     }
 
-    url = showdown.helper.escapeCharacters(url, '*_', false);
+    //url = showdown.helper.escapeCharacters(url, '*_', false); // replaced line to improve performance
+    url = url.replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
+
     var result = '<a href="' + url + '"';
 
     if (title !== '' && title !== null) {
       title = title.replace(/"/g, '&quot;');
-      title = showdown.helper.escapeCharacters(title, '*_', false);
+      //title = showdown.helper.escapeCharacters(title, '*_', false); // replaced line to improve performance
+      title = title.replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
       result += ' title="' + title + '"';
     }
 

src/subParsers/encodeCode.js

@@ -8,14 +8,15 @@ showdown.subParser('encodeCode', function (text) {
 
   // Encode all ampersands; HTML entities are not
   // entities within a Markdown code span.
-  text = text.replace(/&/g, '&');
-
+  text = text
+    .replace(/&/g, '&')
   // Do the angle bracket song and dance:
-  text = text.replace(/</g, '&lt;');
-  text = text.replace(/>/g, '&gt;');
+    .replace(/</g, '&lt;')
+    .replace(/>/g, '&gt;')
 
   // Now, escape characters that are magic in Markdown:
-  text = showdown.helper.escapeCharacters(text, '*_{}[]\\', false);
+  //text = showdown.helper.escapeCharacters(text, '*_{}[]\\', false); // replaced line to improve performance
+    .replace(/([*_{}\[\]\\])/g, showdown.helper.escapeCharactersCallback);
 
   // jj the line above breaks this:
   //---

src/subParsers/escapeSpecialCharsWithinTagAttributes.js

@@ -10,9 +10,10 @@ showdown.subParser('escapeSpecialCharsWithinTagAttributes', function (text) {
   var regex = /(<[a-z\/!$]("[^"]*"|'[^']*'|[^'">])*>|<!(--.*?--\s*)+>)/gi;
 
   text = text.replace(regex, function (wholeMatch) {
-    var tag = wholeMatch.replace(/(.)<\/?code>(?=.)/g, '$1`');
-    tag = showdown.helper.escapeCharacters(tag, '\\`*_', false);
-    return tag;
+    return wholeMatch
+      .replace(/(.)<\/?code>(?=.)/g, '$1`')
+    //tag = showdown.helper.escapeCharacters(tag, '\\`*_', false);
+      .replace(/([\\`*_])/g, showdown.helper.escapeCharactersCallback);
   });
 
   return text;

src/subParsers/images.js

@@ -42,14 +42,19 @@ showdown.subParser('images', function (text, options, globals) {
       }
     }
 
-    altText = altText.replace(/"/g, '"');
-    altText = showdown.helper.escapeCharacters(altText, '*_', false);
-    url = showdown.helper.escapeCharacters(url, '*_', false);
+    altText = altText
+      .replace(/"/g, '"')
+    //altText = showdown.helper.escapeCharacters(altText, '*_', false);
+      .replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
+    //url = showdown.helper.escapeCharacters(url, '*_', false);
+    url = url.replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
     var result = '<img src="' + url + '" alt="' + altText + '"';
 
     if (title) {
-      title = title.replace(/"/g, '&quot;');
-      title = showdown.helper.escapeCharacters(title, '*_', false);
+      title = title
+        .replace(/"/g, '&quot;')
+      //title = showdown.helper.escapeCharacters(title, '*_', false);
+        .replace(showdown.helper.regexes.asteriskAndDash, showdown.helper.escapeCharactersCallback);
       result += ' title="' + title + '"';
     }
 

test/cases/code-block-with-special-chars.html

@@ -0,0 +1,7 @@
+<pre><code>//**this** code _has_ special chars
+var arr = ['foo', 'bar', 'baz'];
+function () {
+    return 'foo';
+}
+\n
+</code></pre>

test/cases/code-block-with-special-chars.md

@@ -0,0 +1,6 @@
+    //**this** code _has_ special chars
+    var arr = ['foo', 'bar', 'baz'];
+    function () {
+        return 'foo';
+    }
+    \n