const a = new cloud.Cloud({
      identityless: true,
      resourceAppid: '小程序Id',
      resourceEnv: '云环境Id'
  })
  document.querySelector('#button').onclick = async() => {
    await a.init()
    let res
    res = await a.callFunction({
      name: 'login',
      data: {}
    })
    console.log(res)
  }