overleaf/services/web/frontend/js/features/source-editor/extensions/folding-keymap.ts

import { keymap } from '@codemirror/view'
import { foldAll, toggleFold, unfoldAll } from '@codemirror/language'

export function foldingKeymap() {
  return keymap.of([
    {
      key: 'F2',
      run: toggleFold,
    },
    {
      key: 'Alt-Shift-1',
      run: foldAll,
    },
    {
      key: 'Alt-Shift-0',
      run: unfoldAll,
    },
  ])
}