Add alt handling

packages/break/test/index.js

@@ -70,9 +70,7 @@ test('fixtures', async function (t) {
         // We could do this, if we operated in the parser.
         // To do: consider `micromark-extension-github-break`?
         .replace(/(<p>Character)<br>(\nreference break\.<\/p>)/, '$1$2')
-        // GitHub removes line endings in `alt` on image it seems?
-        // To do: investigate.
-        // CommonMark doesn’t seem to do that.
+        // See `rehype-github-image` — GH removes line endings in `alt` on image.
         .replace(/(alt="im)\n(age")/, '$1 $2')
         // GitHub drops HTML comments.
         .replace(/<!--[\s\S]*?-->/g, '')

packages/image/lib/index.js

@@ -52,6 +52,8 @@ import {visitParents} from 'unist-util-visit-parents'
  */
 const magicDefaultHostname = 'example.com'
 
+const lineEnding = /\r?\n/g
+
 /** @type {Options} */
 const emptyOptions = {}
 /** @type {[]} */
@@ -129,17 +131,23 @@ export default function rehypeGithubImage(options) {
 
     /** @type {BuildVisitor<Root, 'element'>} */
     function onelement(node, parents) {
-      if (
-        node.type === 'element' &&
-        node.tagName === 'img' &&
-        node.properties
-      ) {
+      if (node.type === 'element' && node.tagName === 'img') {
         let fragment = node
         const sources = [fragment]
         const raw = node.properties.src
         const [source, proxy] = sanitizeSource(raw, toProxyUrl, internal)
 
         if (proxy) node.properties.dataCanonicalSrc = raw
+
+        // GitHub removes line endings in `alt` on images.
+        // CommonMark doesn’t seem to do that.
+        if (node.properties.alt !== null && node.properties.alt !== undefined) {
+          node.properties.alt = String(node.properties.alt).replace(
+            lineEnding,
+            ' '
+          )
+        }
+
         node.properties.src = ''
         node.properties.style = 'max-width: 100%;'
 

packages/image/test/fixtures/alt.html

@@ -0,0 +1,7 @@
+<p>alpha <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="x y" style="max-width: 100%;"></a></p>
+<p>bravo <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="x " style="max-width: 100%;"></a></p>
+<p>charlie <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt=" y" style="max-width: 100%;"></a></p>
+<p>delta <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt=" x y" style="max-width: 100%;"></a></p>
+<p>echo <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="x y " style="max-width: 100%;"></a></p>
+<p>foxtrot <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="  x y" style="max-width: 100%;"></a></p>
+<p>golf <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="x y  " style="max-width: 100%;"></a></p>

packages/image/test/fixtures/alt.md

@@ -0,0 +1,20 @@
+alpha ![x
+y](z)
+
+bravo ![x
+](z)
+
+charlie ![
+y](z)
+
+delta ![ x
+y](z)
+
+echo ![x
+y ](z)
+
+foxtrot ![  x
+y](z)
+
+golf ![x
+y  ](z)

packages/image/test/fixtures/title.html

@@ -0,0 +1,14 @@
+<p>alpha <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="" title="x
+y" style="max-width: 100%;"></a></p>
+<p>bravo <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="" title="x
+" style="max-width: 100%;"></a></p>
+<p>charlie <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="" title="
+y" style="max-width: 100%;"></a></p>
+<p>delta <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="" title=" x
+y" style="max-width: 100%;"></a></p>
+<p>echo <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="" title="x
+y " style="max-width: 100%;"></a></p>
+<p>foxtrot <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="" title="  x
+y" style="max-width: 100%;"></a></p>
+<p>golf <a target="_blank" rel="noopener noreferrer" href="z"><img src="z" alt="" title="x
+y  " style="max-width: 100%;"></a></p>

packages/image/test/fixtures/title.md

@@ -0,0 +1,20 @@
+alpha ![](z "x
+y")
+
+bravo ![](z "x
+")
+
+charlie ![](z "
+y")
+
+delta ![](z " x
+y")
+
+echo ![](z "x
+y ")
+
+foxtrot ![](z "  x
+y")
+
+golf ![](z "x
+y  ")