relocate addMultiCursor

packages/editor/src/client/services/use-codemirror-editor/utils/add-multi-cursor.ts

@@ -0,0 +1,49 @@
+import { useCallback } from 'react';
+
+import type { SelectionRange } from '@codemirror/state';
+import { EditorSelection } from '@codemirror/state';
+import type { EditorView, Command } from '@codemirror/view';
+
+
+const addMultiCursor = (view: EditorView, direction: 'up' | 'down') => {
+
+  const selection = view.state.selection;
+  const doc = view.state.doc;
+  const ranges = selection.ranges;
+  const newRanges: SelectionRange[] = [];
+
+  ranges.forEach((range) => {
+
+    const head = range.head;
+    const line = doc.lineAt(head);
+    const targetLine = direction === 'up' ? line.number - 1 : line.number + 1;
+
+    if (targetLine < 1 || targetLine > doc.lines) return;
+
+    const targetLineText = doc.line(targetLine);
+
+    const col = Math.min(range.head - line.from, targetLineText.length);
+    const cursorPos = targetLineText.from + col;
+
+    newRanges.push(EditorSelection.cursor(cursorPos));
+
+  });
+
+  if (newRanges.length) {
+    const transaction = {
+      selection: EditorSelection.create([...ranges, ...newRanges]),
+    };
+
+    view.dispatch(transaction);
+  }
+
+  return true;
+};
+
+export const useAddMultiCursorCommand = (direction: 'up' | 'down'): Command => {
+  return useCallback((view?: EditorView) => {
+    if (view == null) return false;
+    addMultiCursor(view, direction);
+    return true;
+  }, [direction]);
+};