Add support for ignoring from attributes

Author: wooorm

lib/one.js

@@ -9,8 +9,14 @@ var own = {}.hasOwnProperty;
 function one(h, node, parent) {
   var fn = null;
 
-  if (node.type === 'element' && own.call(h.handlers, node.tagName)) {
-    fn = h.handlers[node.tagName];
+  if (node.type === 'element') {
+    if (node.properties && node.properties.dataMdast === 'ignore') {
+      return;
+    }
+
+    if (own.call(h.handlers, node.tagName)) {
+      fn = h.handlers[node.tagName];
+    }
   } else if (own.call(h.handlers, node.type)) {
     fn = h.handlers[node.type];
   }

readme.md

@@ -87,7 +87,7 @@ An implicit sentence.
 # An explicit sentence.
 ```
 
-###### Ignored nodes
+###### Ignoring nodes
 
 Some nodes are ignored and their content will not be present in MDAST.
 To ignore custom elements, configure a handler for their tag-name or type that
@@ -104,6 +104,18 @@ Yields:
 **Importance** and .
 ```
 
+To ignore a specific element from HTML, set `data-mdast` to `ignore`:
+
+```html
+<p><strong>Importance</strong> and <em data-mdast="ignore">emphasis</em>.</p>
+```
+
+Yields:
+
+```markdown
+**Importance** and .
+```
+
 ## Related
 
 *   [`mdast-util-to-hast`][mdast-util-to-hast]

test/fixtures/ignore/index.html

@@ -0,0 +1 @@
+<p><strong>Importance</strong> and <em data-mdast="ignore">emphasis</em>.</p>

test/fixtures/ignore/index.json

@@ -0,0 +1,3 @@
+{
+  "fragment": true
+}

test/fixtures/ignore/index.md

@@ -0,0 +1 @@
+**Importance** and .