fix: check isContentEditable of target element in ReactEditor.hasDOMNode (#3389)

* fix ReactEditor.hasDOMNode

* make ReactEditor.hasDOMNode variables more clear

packages/slate-react/src/plugin/react-editor.ts

@@ -149,15 +149,17 @@ export const ReactEditor = {
     options: { editable?: boolean } = {}
   ): boolean {
     const { editable = false } = options
-    const el = ReactEditor.toDOMNode(editor, editor)
-    let element
+    const editorEl = ReactEditor.toDOMNode(editor, editor)
+    let targetEl
 
     // COMPAT: In Firefox, reading `target.nodeType` will throw an error if
     // target is originating from an internal "restricted" element (e.g. a
     // stepper arrow on a number input). (2018/05/04)
     // https://github.com/ianstormtaylor/slate/issues/1819
     try {
-      element = isDOMElement(target) ? target : target.parentElement
+      targetEl = (isDOMElement(target)
+        ? target
+        : target.parentElement) as HTMLElement
     } catch (err) {
       if (
         !err.message.includes('Permission denied to access property "nodeType"')
@@ -166,13 +168,13 @@ export const ReactEditor = {
       }
     }
 
-    if (!element) {
+    if (!targetEl) {
       return false
     }
 
     return (
-      element.closest(`[data-slate-editor]`) === el &&
-      (!editable || el.isContentEditable)
+      targetEl.closest(`[data-slate-editor]`) === editorEl &&
+      (!editable || targetEl.isContentEditable)
     )
   },