fix(merge): fix extensions props issue.

Author: jaywcjlove

merge/src/Internal.tsx

@@ -1,4 +1,5 @@
 import React, { useEffect, useImperativeHandle, useMemo, useRef, memo } from 'react';
+import { EditorStateConfig, Extension, StateEffect, Annotation } from '@codemirror/state';
 import { MergeView, MergeConfig } from '@codemirror/merge';
 import { useStore } from './store';
 import { CodeMirrorMergeProps } from './';
@@ -24,7 +25,7 @@ export const Internal = React.forwardRef((props: CodeMirrorMergeProps, ref?: Rea
   const editor = useRef<HTMLDivElement>(null);
   useImperativeHandle(ref, () => ({ container: editor.current, view }), [editor, view]);
   useEffect(() => {
-    if (!view && editor.current && original && modified) {
+    if (!view && editor.current && original?.extensions && modified?.extensions) {
       const opts = { orientation, revertControls, highlightChanges, gutter, collapseUnchanged, renderRevertControl };
       const viewDefault = new MergeView({
         a: original,

merge/src/Modified.tsx

@@ -32,6 +32,11 @@ export const Modified = (props: ModifiedProps): JSX.Element | null => {
   });
   const extensionsData = [updateListener, ...defaultExtensions, ...extensions];
   const data: EditorStateConfig = { extensions: [...extensionsData] };
+
+  useEffect(() => {
+    dispatch!({ modified: { doc: props.value, selection: props.selection, ...data } });
+  }, []);
+
   useEffect(() => {
     if (modified?.doc !== props.value && view) {
       data.doc = props.value;

merge/src/Original.tsx

@@ -32,6 +32,11 @@ export const Original = (props: OriginalProps): JSX.Element | null => {
   });
   const extensionsData = [updateListener, ...defaultExtensions, ...extensions];
   const data: EditorStateConfig = { extensions: [...extensionsData] };
+
+  useEffect(() => {
+    dispatch!({ original: { doc: props.value, selection: props.selection, ...data } });
+  }, []);
+
   useEffect(() => {
     if (original?.doc !== props.value && view) {
       data.doc = props.value;
@@ -41,6 +46,7 @@ export const Original = (props: OriginalProps): JSX.Element | null => {
         view?.a.dispatch({
           changes: { from: 0, to: (originalDoc || '').length, insert: props.value || '' },
           effects: StateEffect.appendConfig.of([...extensionsData]),
+          annotations: [External.of(true)],
         });
       }
     }