Fix types to always pass node to afterTransform

Author: wooorm

Diff for: lib/index.js

@@ -9,18 +9,17 @@
  * @typedef {HastChild|HastRoot} HastNode
  *
  * @callback AfterTransform
- *   Function called when a DOM node is transformed into a hast node
+ *   Called when a DOM node was transformed into a hast node.
  * @param {Node} domNode
- *   The DOM node that was handled
- * @param {HastNode|undefined} hastNode
- *   The corresponding hast node
+ *   DOM node that was transformed.
+ * @param {HastNode} hastNode
+ *   hast node the transform yielded.
  * @returns {void}
+ *   Nothing.
  *
  * @typedef Options
  * @property {AfterTransform} [afterTransform]
- *   Function called after a DOM node is transformed into a hast node.
- *   Given the DOM node that was handled as the first parameter and the
- *   corresponding hast node as the second parameter.
+ *   Called when a DOM node was transformed into a hast node.
  */
 
 import {webNamespaces} from 'web-namespaces'
@@ -56,7 +55,7 @@ export function fromDom(node, options = {}) {
  */
 function transform(node, ctx) {
   const transformed = one(node, ctx)
-  if (ctx.afterTransform) ctx.afterTransform(node, transformed)
+  if (ctx.afterTransform && transformed) ctx.afterTransform(node, transformed)
   return transformed
 }