how to sort a table in alphabetical order with antd

I want to filter the column in alphabetical order here is the code to filter by the size how to do thank you

const columns = [{
      title: 'First Name',
      dataIndex: 'first_name',
      sortDirections: ['descend', 'ascend'],
      key: 'first_name',
      width: '20%',
      sorter: (a, b) => a.first_name.length - b.first_name.length,

    }]

You can use localeCompare()

sorter: (a, b) => a.first_name.localeCompare(b.first_name);