Github Task Lists

Add support for Github Task Lists under the gfm flag.

Changes to API

* list(*string* body, *boolean* ordered, *boolean* taskList)
* listitem(*string* text, [*boolean* checked]).

`checked` is defined when you have a list item which starts with `[ ] ` or
`[x] `.If defined its a boolean depending on whether the `x` is
present. When checked is defined we add a input type type `checkbox` to
the list item and add the class `task-list-item-checkbox`.

`taskList` is true if a list has any list items where `checked` is
defined. When true we add the class `task-list` to the list.

Resolves #107

Author: jhollingworth

README.md

@@ -188,7 +188,8 @@ This code will output the following HTML:
 - html(*string* html)
 - heading(*string* text, *number*  level)
 - hr()
-- list(*string* body, *boolean* ordered)
+- list(*string* body, *boolean* ordered, *boolean* taskList)
+  - `taskList` true when `gfm` is `true` and there is a list item with a check box
 - listitem(*string*  text)
 - paragraph(*string* text)
 - table(*string* header, *string* body)
@@ -211,7 +212,8 @@ This code will output the following HTML:
 - codespan(*string* code)
 - br()
 - del(*string* text)
-- link(*string* href, *string* title, *string* text)
+- link(*string* href, *string* title, *string* text, [*boolean* checked]).
+  - `checked` only defined when `gfm` is `true` and there is a check box at the start of the list item (e.g. `* [ ] foo`).
 - image(*string* href, *string* title, *string* text)
 
 ### gfm

lib/marked.js

@@ -27,6 +27,7 @@ var block = {
   text: /^[^\n]+/
 };
 
+block.checkbox = /^\[([ x])\] +/;
 block.bullet = /(?:[*+-]|\d+\.)/;
 block.item = /^( *)(bull) [^\n]*(?:\n(?!\1bull )[^\n]*)*/;
 block.item = replace(block.item, 'gm')
@@ -156,7 +157,8 @@ Lexer.prototype.token = function(src, top, bq) {
     , item
     , space
     , i
-    , l;
+    , l
+    , checked;
 
   while (src) {
     // newline
@@ -303,6 +305,17 @@ Lexer.prototype.token = function(src, top, bq) {
         space = item.length;
         item = item.replace(/^ *([*+-]|\d+\.) +/, '');
 
+        if (this.options.gfm) {
+          checked = block.checkbox.exec(item);
+
+          if (checked) {
+            checked = checked[1] === 'x';
+            item = item.replace(block.checkbox, '');
+          } else {
+            checked = undefined;
+          }
+        }
+
         // Outdent whatever the
         // list item contains. Hacky.
         if (~item.indexOf('\n ')) {
@@ -332,6 +345,7 @@ Lexer.prototype.token = function(src, top, bq) {
         }
 
         this.tokens.push({
+          checked: checked,
           type: loose
             ? 'loose_item_start'
             : 'list_item_start'
@@ -802,13 +816,23 @@ Renderer.prototype.hr = function() {
   return this.options.xhtml ? '<hr/>\n' : '<hr>\n';
 };
 
-Renderer.prototype.list = function(body, ordered) {
+Renderer.prototype.list = function(body, ordered, taskList) {
   var type = ordered ? 'ol' : 'ul';
-  return '<' + type + '>\n' + body + '</' + type + '>\n';
+  var classes = taskList ? ' class="task-list"' : '';
+  return '<' + type + classes + '>\n' + body + '</' + type + '>\n';
 };
 
-Renderer.prototype.listitem = function(text) {
-  return '<li>' + text + '</li>\n';
+Renderer.prototype.listitem = function(text, checked) {
+  if (checked === undefined) {
+    return '<li>' + text + '</li>\n';
+  }
+
+  return '<li class="task-list-item">'
+    + '<input type="checkbox" class="task-list-item-checkbox"'
+    + (checked ? ' checked' : '')
+    + '> '
+    + text
+    + '</li>\n';
 };
 
 Renderer.prototype.paragraph = function(text) {
@@ -1026,24 +1050,30 @@ Parser.prototype.tok = function() {
     }
     case 'list_start': {
       var body = ''
+        , taskList = false
         , ordered = this.token.ordered;
 
       while (this.next().type !== 'list_end') {
+        if (this.token.checked !== undefined) {
+          taskList = true;
+        }
+
         body += this.tok();
       }
 
-      return this.renderer.list(body, ordered);
+      return this.renderer.list(body, ordered, taskList);
     }
     case 'list_item_start': {
-      var body = '';
+      var body = ''
+        , checked = this.token.checked;
 
       while (this.next().type !== 'list_item_end') {
         body += this.token.type === 'text'
           ? this.parseText()
           : this.tok();
       }
 
-      return this.renderer.listitem(body);
+      return this.renderer.listitem(body, checked);
     }
     case 'loose_item_start': {
       var body = '';
@@ -1052,7 +1082,7 @@ Parser.prototype.tok = function() {
         body += this.tok();
       }
 
-      return this.renderer.listitem(body);
+      return this.renderer.listitem(body, checked);
     }
     case 'html': {
       var html = !this.token.pre && !this.options.pedantic

test/tests/gfm_task_list.html

@@ -0,0 +1,11 @@
+<ul class="task-list">
+<li class="task-list-item"><input type="checkbox" class="task-list-item-checkbox"> foo</li>
+<li>bar</li>
+<li class="task-list-item"><input type="checkbox" class="task-list-item-checkbox" checked> baz</li>
+<li>[] bam
+<ul class="task-list">
+<li class="task-list-item"><input type="checkbox" class="task-list-item-checkbox"> bim</li>
+<li class="task-list-item"><input type="checkbox" class="task-list-item-checkbox"> lim</li>
+</ul>
+</li>
+</ul>

test/tests/gfm_task_list.text

@@ -0,0 +1,6 @@
+* [ ] foo
+* bar
+* [x] baz
+* [] bam
+  * [ ] bim
+  * [ ] lim