How to use the slate.Editor.nodes function in slate

const isFormatActive = (editor, format) => {
  const [match] = Editor.nodes(editor, {
    match: n => n[format] === true,
    mode: 'all',
  })
  return !!match
}

const isBlockActive = (editor, format) => {
  const [match] = Editor.nodes(editor, {
    match: n => n.type === format,
  })

  return !!match
}

editor.deleteBackward = unit => {
    const { selection } = editor

    if (selection && Range.isCollapsed(selection)) {
      const [cell] = Editor.nodes(editor, {
        match: n => n.type === 'table-cell',
      })

      if (cell) {
        const [, cellPath] = cell
        const start = Editor.start(editor, cellPath)

        if (Point.equals(selection.anchor, start)) {
          return
        }
      }
    }

    deleteBackward(unit)
  }

editor.deleteBackward = (...args) => {
    const { selection } = editor

    if (selection && Range.isCollapsed(selection)) {
      const [match] = Editor.nodes(editor, {
        match: n => n.type === 'check-list-item',
      })

      if (match) {
        const [, path] = match
        const start = Editor.start(editor, path)

        if (Point.equals(selection.anchor, start)) {
          Transforms.setNodes(
            editor,
            { type: 'paragraph' },
            { match: n => n.type === 'check-list-item' }
          )
          return
        }
      }

export function isMarkActive(editor: Editor, mark: string) {
  const [match] = SlateEditor.nodes(editor, {
    match(node) {
      return node[mark]
    }
  })
  return Boolean(match)
}