Changes after code review. Escape certain characters only when used i…

…n valid markdown.

src/turndown.js

@@ -6,23 +6,21 @@ import Node from './node'
 var reduce = Array.prototype.reduce
 var leadingNewLinesRegExp = /^\n*/
 var trailingNewLinesRegExp = /\n*$/
-const markdownReplacements = [
+var escapes = [
   [/\\/g, '\\\\'],
   [/\*/g, '\\*'],
   [/-/g, '\\-'],
-  [/\+/g, '\\+'],
-  [/=/g, '\\='],
-  [/#/g, '\\#'],
+  [/^\+ /g, '\\+ '],
+  [/^(=+)/g, '\\$1'],
+  [/^(#{1,6}) /g, '\\$1 '],
   [/`/g, '\\`'],
   [/~/g, '\\~'],
   [/\|/g, '\\|'],
-  [/\(/g, '\\('],
-  [/\)/g, '\\)'],
   [/\[/g, '\\['],
   [/\]/g, '\\]'],
-  [/>/g, '\\>'],
+  [/^>/g, '\\>'],
   [/_/g, '_'],
-  [/(\d+)\./g, '$1\\.']
+  [/^(\d+)\. /g, '$1\\. ']
 ]
 
 export default function TurndownService (options) {
@@ -144,10 +142,9 @@ TurndownService.prototype = {
    */
 
   escape: function (string) {
-    return markdownReplacements.reduce(
-      (search, replacement) => search.replace(replacement[0], replacement[1]),
-      string
-    )
+    return escapes.reduce(function (accumulator, escape) {
+      return accumulator.replace(escape[0], escape[1])
+    }, string)
   }
 }
 

test/index.html

@@ -88,6 +88,16 @@
 =================</pre>
 </div>
 
+<div class="case" data-name="escape = when used as heading">
+  <div class="input">===</div>
+  <pre class="expected">\===</pre>
+</div>
+
+<div class="case" data-name="do not escape = outside of a heading">
+  <div class="input">A sentence containing =</div>
+  <pre class="expected">A sentence containing =</pre>
+</div>
+
 <div class="case" data-name="h1 as atx" data-options='{"headingStyle":"atx"}'>
   <div class="input"><h1>Level One Heading with ATX</h1></div>
   <pre class="expected"># Level One Heading with ATX</pre>
@@ -671,7 +681,12 @@ <h2>This is a header.</h2>
 
 <div class="case" data-name="escaping headings with #">
   <div class="input">### This is not a heading</div>
-  <pre class="expected">\#\#\# This is not a heading</pre>
+  <pre class="expected">\### This is not a heading</pre>
+</div>
+
+<div class="case" data-name="do not escape # outside of a heading">
+  <div class="input">#This is not # a heading</div>
+  <pre class="expected">#This is not # a heading</pre>
 </div>
 
 <div class="case" data-name="escaping em markdown with *">
@@ -729,9 +744,9 @@ <h2>This is a header.</h2>
   <pre class="expected">1984\. by George Orwell</pre>
 </div>
 
-<div class="case" data-name="escaping numbers followed by a full stop in a sentence">
-  <div class="input">George Orwell wrote 1984.</div>
-  <pre class="expected">George Orwell wrote 1984\.</pre>
+<div class="case" data-name="do not escape . outside of an ol">
+  <div class="input">1984.George Orwell wrote 1984.</div>
+  <pre class="expected">1984.George Orwell wrote 1984.</pre>
 </div>
 
 <div class="case" data-name="escaping ul markdown *">
@@ -749,9 +764,9 @@ <h2>This is a header.</h2>
   <pre class="expected">\+ An unordered list item</pre>
 </div>
 
-<div class="case" data-name="escaping =">
-  <div class="input">A sentence containing =</div>
-  <pre class="expected">A sentence containing \=</pre>
+<div class="case" data-name="do not escape + outside of a ul">
+  <div class="input">+1 and another +</div>
+  <pre class="expected">+1 and another +</pre>
 </div>
 
 <div class="case" data-name="escaping ~">
@@ -764,11 +779,6 @@ <h2>This is a header.</h2>
   <pre class="expected">A sentence containing \|</pre>
 </div>
 
-<div class="case" data-name="escaping parentheses">
-  <div class="input">(A sentence containing)</div>
-  <pre class="expected">\(A sentence containing\)</pre>
-</div>
-
 <div class="case" data-name="escaping *">
   <div class="input">You can use * for multiplication</div>
   <pre class="expected">You can use \* for multiplication</pre>
@@ -785,23 +795,23 @@ <h2>This is a header.</h2>
 </div>
 
 <div class="case" data-name="escaping -">
-  <div class="input">45.5 - 3.5 = 42</div>
-  <pre class="expected">45\.5 \- 3\.5 \= 42</pre>
-</div>
-
-<div class="case" data-name="escaping +">
-  <div class="input">+1</div>
-  <pre class="expected">\+1</pre>
+  <div class="input">45 - 3 is 42</div>
+  <pre class="expected">45 \- 3 is 42</pre>
 </div>
 
 <div class="case" data-name="escaping > as blockquote">
   <div class="input">> Blockquote in markdown</div>
   <pre class="expected">\> Blockquote in markdown</pre>
 </div>
 
-<div class="case" data-name="escaping > within text">
+<div class="case" data-name="escaping > as blockquote without space">
+  <div class="input">>Blockquote in markdown</div>
+  <pre class="expected">\>Blockquote in markdown</pre>
+</div>
+
+<div class="case" data-name="do not escape > outside of a blockquote">
   <div class="input">42 > 1</div>
-  <pre class="expected">42 \> 1</pre>
+  <pre class="expected">42 > 1</pre>
 </div>
 
 <div class="case" data-name="escaping code">