Add onComplete callback for completing processing in MarkdownHooks

lib/index.js

@@ -82,6 +82,8 @@
  *   Configuration specifically for {@linkcode MarkdownHooks}.
  * @property {ReactNode | null | undefined} [fallback]
  *   Content to render while the processor processing the markdown (optional).
+ * @property {(file: VFile, hast: Root | undefined, error: Error | undefined) => unknown} [onComplete]
+ *   Callback when the processor is done processing.
  */
 
 /**
@@ -232,6 +234,7 @@ export function MarkdownHooks(options) {
         if (!cancelled) {
           setError(error)
           setTree(tree)
+          options.onComplete?.(file, tree, error)
         }
       })
 
@@ -243,7 +246,7 @@ export function MarkdownHooks(options) {
         cancelled = true
       }
     },
-    [options.children, processor]
+    [options.children, processor, options.onComplete]
   )
 
   if (error) throw error

test.jsx

@@ -1167,6 +1167,30 @@ test('MarkdownHooks', async function (t) {
     assert.equal(result.container.innerHTML, '<p>a</p>')
   })
 
+  await t.test('should support `onComplete`', async function () {
+    const plugin = deferPlugin()
+    let succes = false
+    render(
+      <MarkdownHooks
+        children={'a'}
+        onComplete={function () {
+          succes = true
+        }}
+        rehypePlugins={[plugin.plugin]}
+      />
+    )
+
+    assert.equal(succes, false)
+
+    plugin.resolve()
+
+    await waitFor(function () {
+      assert.notEqual(succes, false)
+    })
+
+    assert.equal(succes, true)
+  })
+
   await t.test('should support plugins that error', async function () {
     const plugin = deferPlugin()
     const result = render(