extensions = [
CodeMirror.history(),
CodeMirror.drawSelection(),
CodeMirror.EditorState.allowMultipleSelections.of(true),
CodeMirror.gutter(),
CodeMirror.lineNumbers(),
CodeMirror.highlightActiveLine(),
CodeMirror.keymap.of([
...CodeMirror.defaultKeymap,
...CodeMirror.historyKeymap
]),
CodeMirror.oneDark
]