fix: marks at the start of the selection (#5725)

* fix: marks at the start of the selection

* chore: modify unit test description

.changeset/odd-falcons-hang.md

@@ -0,0 +1,5 @@
+---
+'slate': patch
+---
+
+fix marks at the start of the selection

packages/slate/src/editor/marks.ts

@@ -19,6 +19,10 @@ export const marks: EditorInterface['marks'] = (editor, options = {}) => {
   }
 
   if (Range.isExpanded(selection)) {
+    const isBackward = Range.isBackward(selection)
+    if (isBackward) {
+      ;[focus, anchor] = [anchor, focus]
+    }
     /**
      * COMPAT: Make sure hanging ranges (caused by double clicking in Firefox)
      * do not adversely affect the returned marks.

packages/slate/test/interfaces/Editor/marks/focus-block-end.tsx

@@ -0,0 +1,36 @@
+/** @jsx jsx */
+import { Editor } from 'slate'
+import { jsx } from '../../..'
+
+/**
+ * Similar to firefox-double-click.tsx, when the selection is at the end of
+ * the previous node's path, using Editor.marks retrieves the marks of that node.
+ * However, when addMark is triggered, that node is not within the range for
+ * adding marks,  thus failing to transfer the state correctly.
+ */
+
+export const input = (
+  <editor>
+    <block>
+      <text>
+        block one
+        <focus />
+      </text>
+    </block>
+    <block>
+      <text bold>block two</text>
+    </block>
+    <block>
+      <text bold>
+        block three
+        <anchor />
+      </text>
+    </block>
+  </editor>
+)
+
+export const test = editor => {
+  return Editor.marks(editor)
+}
+
+export const output = { bold: true }