如何在 Object 字面键中使用表达式？

问：

我有一个开关^

  let s = "aaa"

  switch (true) {
    case s.includes('a'):
      url = 'https://a.com/wp-admin/post-new.php'
      console.log(url)
      break
    case s.includes('b'):
      url = 'https://b.com/wp-admin/post-new.php'
      console.log(url)
      break
    default:
      console.log('default')
      break
  }

我正在尝试将其更改为文字对象，但我无法弄清楚如何正确指定 s.includes 条件作为对象键

  const objLit = (s) => {
    const cases = {
      //s.includes('a'): 'https://a.com/wp-admin/post-new.php',
      [`${s.includes('a')}`]: 'https://a.com/wp-admin/post-new.php',
      //s.includes('b'): 'https://b.com/wp-admin/post-new.php',
      [`${s.includes('b')}`]: 'https://b.com/wp-admin/post-new.php',
    }

    let url = cases[s]
    return url

  }

  console.log(objLit(s))

虽然这不会引发错误，但它不起作用。