feat: Add getParentContainer() helper function.

Author: jenstroeger

src/cursor.js

@@ -289,6 +289,21 @@ export default class Cursor {
     return content.adoptElement(node, this.win.document)
   }
 
+  // Check whether the cursor's closest parent element node matches
+  // the given tagName (and optional className), and return that
+  // parent if it does or null if not.
+  getParentContainer (tagName, className) {
+    const container = this.range.startContainer
+
+    if (container.nodeType !== Node.TEXT_NODE) return null
+
+    const parent = container.parentElement
+    if (parent.nodeName !== tagName) return null
+    if (className && !parent.classList.contains(className)) return null
+
+    return parent
+  }
+
   // Currently we call triggerChange manually after format changes.
   // This is to prevent excessive triggering of the change event during
   // merge or split operations or other manipulations by scripts.