Fix to filter out initial, final <br>s

Closes GH-66.

Author: wooorm

lib/all.js

@@ -18,17 +18,39 @@ export function all(h, parent) {
   // @ts-expect-error Assume `parent` is a parent.
   const nodes = parent.children || []
   /** @type {Array.<MdastNode>} */
-  let values = []
+  const values = []
   let index = -1
-  /** @type {MdastNode|Array.<MdastNode>} */
-  let result
+  let length = nodes.length
+  let child = nodes[index + 1]
 
-  while (++index < nodes.length) {
+  // Trim initial and final `<br>`s.
+  // They’re not semantic per HTML, and they can’t be made in markdown things
+  // like paragraphs or headings.
+  while (child && child.type === 'element' && child.tagName === 'br') {
+    index++
+    child = nodes[index + 1]
+  }
+
+  child = nodes[length - 1]
+
+  while (
+    length - 1 > index &&
+    child &&
+    child.type === 'element' &&
+    child.tagName === 'br'
+  ) {
+    length--
+    child = nodes[length - 1]
+  }
+
+  while (++index < length) {
     // @ts-expect-error assume `parent` is a parent.
-    result = one(h, nodes[index], parent)
+    const result = one(h, nodes[index], parent)
 
-    if (result) {
-      values = values.concat(result)
+    if (Array.isArray(result)) {
+      values.push(...result)
+    } else if (result) {
+      values.push(result)
     }
   }
 

test/fixtures/br/index.html

@@ -1,2 +1,11 @@
 <p>alpha<br>bravo</p>
 <pre>charlie<br>delta</pre>
+<p><br></p>
+<p>echo<br></p>
+<p>foxtrot<br><br></p>
+<p><br>golf</p>
+<p><br><br>hotel</p>
+<p><br>india<br></p>
+<p><br><br>juliett<br><br></p>
+<h1><br>kilo</h1>
+<h1>lima<br></h1>

test/fixtures/br/index.md

@@ -3,3 +3,19 @@ bravo
 
     charlie
     delta
+
+echo
+
+foxtrot
+
+golf
+
+hotel
+
+india
+
+juliett
+
+# kilo
+
+# lima