fix copying mentions as plain text

packages/core/src/extensions/clipboardTextSerializer.ts

@@ -0,0 +1,60 @@
+import { Editor } from '@tiptap/core'
+import { Plugin, PluginKey } from 'prosemirror-state'
+import { Extension } from '../Extension'
+
+const textBetween = (
+  editor: Editor,
+  from: number,
+  to: number,
+  blockSeparator?: string,
+  leafText?: string,
+): string => {
+  let text = ''
+  let separated = true
+
+  editor.state.doc.nodesBetween(from, to, (node, pos) => {
+    const textSerializer = editor.extensionManager.textSerializers[node.type.name]
+
+    if (textSerializer) {
+      text += textSerializer({ node })
+      separated = !blockSeparator
+    } else if (node.isText) {
+      text += node?.text?.slice(Math.max(from, pos) - pos, to - pos)
+      separated = !blockSeparator
+    } else if (node.isLeaf && leafText) {
+      text += leafText
+      separated = !blockSeparator
+    } else if (!separated && node.isBlock) {
+      text += blockSeparator
+      separated = true
+    }
+  }, 0)
+
+  return text
+}
+
+export const ClipboardTextSerializer = Extension.create({
+  name: 'editable',
+
+  addProseMirrorPlugins() {
+    return [
+      new Plugin({
+        key: new PluginKey('clipboardTextSerializer'),
+        props: {
+          clipboardTextSerializer: () => {
+            const { editor } = this
+            const { from, to } = editor.state.selection
+
+            return textBetween(editor, from, to, '\n')
+          },
+        },
+      }),
+    ]
+  },
+})
+
+declare module '@tiptap/core' {
+  interface AllExtensions {
+    ClipboardTextSerializer: typeof ClipboardTextSerializer,
+  }
+}

packages/core/src/extensions/index.ts

@@ -1,3 +1,4 @@
+export { ClipboardTextSerializer } from './clipboardTextSerializer'
 export { Commands } from './commands'
 export { Editable } from './editable'
 export { FocusEvents } from './focusEvents'