无法访问在Switch Statement外声明的变量

Question

我在switch语句之外声明变量contactNumber，然后尝试在switch语句中分配它。但是，当它到达赋值时，我在switch语句中执行的赋值行上得到一个错误SyntaxError: Unexpected identifier

function helplineContactMessageForCountryCode(countryCode) {

    var contactNumber = ''
    switch (countryCode) {
        case 'NG':
        contactNumber = '234-01-772-2200'
        break

        case 'UG':
        contactNumber = '0800-100-330'
        break

        case 'US'
        contactNumber = '1-800-232-4636'
        break

        case 'ZA':
        contactNumber = '0800-012-322'
        break

        default:
        //Return empty string if no country code is found
        return ''
    }
    return 'You can try calling the Toll-Free HIV and AIDS Helpline and speak to a human - ' + contactNumber
}

Answer 1

如果＆＃39; US＆＃39;您缺少：。添加后，它应该像参加者一样工作。

我还建议使用对象映射而不是switch语句为您提供精确的用例，以使代码缩短和更好

function helplineContactMessageForCountryCode(countryCode) {
  const codeMap = {
    NG: '234-01-772-2200',
    UG: '0800-100-330',
    US: '1-800-232-4636',
    ZA: '1-800-232-4636'
  };

  var number = codeMap[countryCode];
  if (number) {
    return 'You can try calling the Toll-Free HIV and AIDS Helpline and speak to a human - ' + number;
  }
  return '';
}

示例中的

代码在helplineContactMessageForCountryCode中设置，但理想情况下应该在其他地方声明它。

Answer 2

您在“美国”:之后错过了case。

function helplineContactMessageForCountryCode(countryCode) {

  var contactNumber = ''
  switch (countryCode) {
    case 'NG':
      contactNumber = '234-01-772-2200';
      break;
    case 'UG':
      contactNumber = '0800-100-330';
      break;
    case 'US':
      contactNumber = '1-800-232-4636';
      break;
    case 'ZA':
      contactNumber = '0800-012-322';
      break;
    default:
      contactNumber = contactNumber;
      break;
  }
  return 'You can try calling the Toll-Free HIV and AIDS Helpline and speak to a human - ' + contactNumber
}