Fix escapes

Author: wooorm

lib/unsafe.js

@@ -38,11 +38,12 @@ module.exports = [
   {atBreak: true, character: '#'},
   // Dollar sign and percentage are not used in markdown.
   // An ampersand could start a character reference.
-  {atBreak: true, character: '&', after: '[#A-Za-z]'},
+  {character: '&', after: '[#A-Za-z]'},
   // An apostrophe can break out of a title.
   {character: "'", inConstruct: 'titleApostrophe'},
   // A left paren could break out of a destination raw.
   {character: '(', inConstruct: 'destinationRaw'},
+  {before: '\\]', character: '(', inConstruct: 'phrasing'},
   // A right paren could start a list item or break out of a destination
   // raw.
   {atBreak: true, before: '\\d+', character: ')'},
@@ -91,7 +92,8 @@ module.exports = [
   // Caret is not used in markdown for constructs.
   // An underscore can start emphasis, strong, or a thematic break.
   {atBreak: true, character: '_'},
-  {character: '_', inConstruct: 'phrasing'},
+  {before: '[^A-Za-z]', character: '_', inConstruct: 'phrasing'},
+  {character: '_', after: '[^A-Za-z]', inConstruct: 'phrasing'},
   // A grave accent can start code (fenced or text), or it can break out of
   // a grave accent code fence.
   {atBreak: true, character: '`'},

test.js

@@ -1156,7 +1156,7 @@ test('imageReference', function (t) {
       identifier: '&b;',
       referenceType: 'full'
     }),
-    '![&a;][&b;]',
+    '![\\&a;][\\&b;]',
     'should support incorrect character references'
   )
 
@@ -1514,7 +1514,7 @@ test('linkReference', function (t) {
       identifier: '&b;',
       referenceType: 'full'
     }),
-    '[&a;][&b;]',
+    '[\\&a;][\\&b;]',
     'should support incorrect character references'
   )
 
@@ -1549,6 +1549,18 @@ test('linkReference', function (t) {
     'should use a full reference if w/o `referenceType` and the label does not match the reference'
   )
 
+  t.equal(
+    to({
+      type: 'paragraph',
+      children: [
+        {type: 'linkReference', children: [{type: 'text', value: 'a'}]},
+        {type: 'text', value: '(b)'}
+      ]
+    }),
+    '[a][]\\(b)',
+    'should use a full reference if w/o `referenceType` and the label does not match the reference'
+  )
+
   t.end()
 })
 
@@ -2345,7 +2357,7 @@ test('escape', function (t) {
 
   t.equal(
     to({type: 'paragraph', children: [{type: 'text', value: '![](a.jpg)'}]}),
-    '\\!\\[](a.jpg)',
+    '\\!\\[]\\(a.jpg)',
     'should escape what would otherwise be an image (resource)'
   )
 
@@ -2357,7 +2369,7 @@ test('escape', function (t) {
 
   t.equal(
     to({type: 'paragraph', children: [{type: 'text', value: '[](a.jpg)'}]}),
-    '\\[](a.jpg)',
+    '\\[]\\(a.jpg)',
     'should escape what would otherwise be a link (resource)'
   )