Fix to use footnote label over identifier

Related to mdx-js/mdx#545.

Closes GH-31

Reviewed-by: Titus Wormer <[email protected]>
Reviewed-by: Christian Murphy <[email protected]>

Author: lehnerpat

lib/handlers/footnote-reference.js

@@ -9,7 +9,7 @@ function footnoteReference(h, node) {
 
   return h(node.position, 'sup', {id: 'fnref-' + identifier}, [
     h(node, 'a', {href: '#fn-' + identifier, className: ['footnote-ref']}, [
-      u('text', identifier)
+      u('text', node.label || identifier)
     ])
   ])
 }

test/footnote-reference.js

@@ -6,35 +6,34 @@ var to = require('..')
 
 test('FootnoteReference', function(t) {
   t.deepEqual(
-    to(
-      u('footnoteReference', {
-        identifier: 'alpha'
-      })
-    ),
-    u(
-      'element',
-      {
-        tagName: 'sup',
-        properties: {
-          id: 'fnref-alpha'
-        }
-      },
-      [
-        u(
-          'element',
-          {
-            tagName: 'a',
-            properties: {
-              href: '#fn-alpha',
-              className: ['footnote-ref']
-            }
-          },
-          [u('text', 'alpha')]
-        )
-      ]
-    ),
+    to(u('footnoteReference', {identifier: 'alpha'})),
+    u('element', {tagName: 'sup', properties: {id: 'fnref-alpha'}}, [
+      u(
+        'element',
+        {
+          tagName: 'a',
+          properties: {href: '#fn-alpha', className: ['footnote-ref']}
+        },
+        [u('text', 'alpha')]
+      )
+    ]),
     'should render `footnoteReference`s'
   )
 
+  t.deepEqual(
+    to(u('footnoteReference', {identifier: 'alpha', label: 'Alpha'})),
+    u('element', {tagName: 'sup', properties: {id: 'fnref-alpha'}}, [
+      u(
+        'element',
+        {
+          tagName: 'a',
+          properties: {href: '#fn-alpha', className: ['footnote-ref']}
+        },
+        [u('text', 'Alpha')]
+      )
+    ]),
+    'should render `footnoteReference`s (#2)'
+  )
+
   t.end()
 })