Fix crash when a void node deletes itself on click (#4616)

* Fix crash when a void node deletes itself on click

Fixes https://github.com/ianstormtaylor/slate/issues/4240

* Add 'image delete' feature to example

My immediate motivation is to demonstrate the bug that this fixes. But
this is also a very common editor feature, and I think it's valuable
to show how to achieve it.

* add changeset

* fix:eslint

* revert changes to mentions.tsx

.changeset/curly-ghosts-look.md

@@ -0,0 +1,5 @@
+---
+'slate-react': patch
+---
+
+Fixed crash on self-deleting void node

packages/slate-react/src/components/editable.tsx

@@ -706,19 +706,29 @@ export const Editable = (props: EditableProps) => {
               ) {
                 const node = ReactEditor.toSlateNode(editor, event.target)
                 const path = ReactEditor.findPath(editor, node)
-                const start = Editor.start(editor, path)
-                const end = Editor.end(editor, path)
 
-                const startVoid = Editor.void(editor, { at: start })
-                const endVoid = Editor.void(editor, { at: end })
+                // At this time, the Slate document may be arbitrarily different,
+                // because onClick handlers can change the document before we get here.
+                // Therefore we must check that this path actually exists,
+                // and that it still refers to the same node.
+                if (Editor.hasPath(editor, path)) {
+                  const lookupNode = Node.get(editor, path)
+                  if (lookupNode === node) {
+                    const start = Editor.start(editor, path)
+                    const end = Editor.end(editor, path)
 
-                if (
-                  startVoid &&
-                  endVoid &&
-                  Path.equals(startVoid[1], endVoid[1])
-                ) {
-                  const range = Editor.range(editor, start)
-                  Transforms.select(editor, range)
+                    const startVoid = Editor.void(editor, { at: start })
+                    const endVoid = Editor.void(editor, { at: end })
+
+                    if (
+                      startVoid &&
+                      endVoid &&
+                      Path.equals(startVoid[1], endVoid[1])
+                    ) {
+                      const range = Editor.range(editor, start)
+                      Transforms.select(editor, range)
+                    }
+                  }
                 }
               }
             },

site/examples/images.tsx

@@ -9,6 +9,7 @@ import {
   useSelected,
   useFocused,
   withReact,
+  ReactEditor,
 } from 'slate-react'
 import { withHistory } from 'slate-history'
 import { css } from 'emotion'
@@ -89,12 +90,20 @@ const Element = props => {
 }
 
 const Image = ({ attributes, children, element }) => {
+  const editor = useSlateStatic()
+  const path = ReactEditor.findPath(editor, element)
+
   const selected = useSelected()
   const focused = useFocused()
   return (
     <div {...attributes}>
       {children}
-      <div contentEditable={false}>
+      <div
+        contentEditable={false}
+        className={css`
+          position: relative;
+        `}
+      >
         <img
           src={element.url}
           className={css`
@@ -104,6 +113,19 @@ const Image = ({ attributes, children, element }) => {
             box-shadow: ${selected && focused ? '0 0 0 3px #B4D5FF' : 'none'};
           `}
         />
+        <Button
+          active
+          onClick={() => Transforms.removeNodes(editor, { at: path })}
+          className={css`
+            display: ${selected && focused ? 'inline' : 'none'};
+            position: absolute;
+            top: 0.5em;
+            left: 0.5em;
+            background-color: white;
+          `}
+        >
+          <Icon>delete</Icon>
+        </Button>
       </div>
     </div>
   )
@@ -159,6 +181,20 @@ const initialValue: Descendant[] = [
       },
     ],
   },
+  {
+    type: 'paragraph',
+    children: [
+      {
+        text:
+          'You can delete images with the cross in the top left. Try deleting this sheep:',
+      },
+    ],
+  },
+  {
+    type: 'image',
+    url: 'https://source.unsplash.com/zOwZKwZOZq8',
+    children: [{ text: '' }],
+  },
 ]
 
 export default ImagesExample