External links

rehype/external-links.js

@@ -0,0 +1,17 @@
+import {visit} from 'unist-util-visit'
+
+export default () => {
+  return (tree) => {
+    visit(tree, 'element', function (node) {
+      if (
+        node.tagName === 'a' &&
+        typeof node.properties.href === 'string'
+      ) {
+        const url = node.properties.href
+        if (url.startsWith('http://') || url.startsWith('https://')) {
+          node.properties.target = '_blank'
+        }
+      }
+    })
+  }
+}