Javascript cron到人类可读的翻译程序

Question

我正在开发一个网页，显示来自GitLab实例的所有项目的计划管道。计划时间用CRON表达式表示，即五位数，如下所示：

因为我的网页的未来用户并不都熟悉CRON表达式，所以我编写了一个脚本，将其转换为人类可读的时间表达式。

理解代码背后的逻辑的一些重要信息：

• 在我的GitLab实例中，"7“不用作"Sunday”的别名。
• 不考虑时区(...yet)。我现在认为所有的CRON表达式都是UTC时代的。
• 时间以24小时格式表示(所以晚上11:23是23h23)
• 我们启动的管道需要很长时间才能完全执行，这就是为什么我们不允许CRON表达式的第一个数字是*。

一些cron到string转换的示例：

0 4***→“每天运行04小时”“023**0→”在星期日的23时运行“041**→”在每个月的第一天运行于04小时。

代码

function convertCronToString(cronExpression) {
  var cron = cronExpression.split(" ");
  var minutes = cron[0];
  var hours = cron[1];
  var dayOfMonth = cron[2];
  var month = cron[3];
  var dayOfWeek = cron[4];

  var cronToString = "Runs at ";

  // Formatting time if composed of zeros
  if (minutes === "0") minutes = "00";
  if (hours === "0") hours = "00";
  // If it's not past noon add a zero before the hour to make it look like "04h00" instead of "4h00"
  else if (hours.length === 1 && hours !== "*") {
    hours = "0" + hours;
  }
  // Our activities do not allow launching pipelines every minute. It won't be processed.
  if (minutes === "*") {
    cronToString =
      "Unreadable cron format. Cron will be displayed in its raw form: " +
      cronExpression;
  }

  cronToString = cronToString + hours + "h" + minutes + " ";

  if (dayOfWeek === "0,6") dayOfWeek = "on weekends";
  else if (dayOfWeek === "1-5") dayOfWeek = "on weekdays";
  else if (dayOfWeek.length === 1) {
    if (dayOfWeek === "*" && dayOfMonth === "*") dayOfWeek = "every day ";
    else if (dayOfWeek === "*" && dayOfMonth !== "*") {
      cronToString = cronToString + "on the " + dayOfMonth;
      if (
        dayOfMonth === "1" ||
        dayOfMonth === "21" ||
        dayOfMonth === "31"
      ) {
        cronToString = cronToString + "st ";
      } else if (dayOfMonth === "2" || dayOfMonth === "22") {
        cronToString = cronToString + "nd ";
      } else if (dayOfMonth === "3" || dayOfMonth === "23") {
        cronToString = cronToString + "rd ";
      } else {
        cronToString = cronToString + "th ";
      }
      cronToString = cronToString + "day of every month";
      return cronToString;
    } else if (dayOfWeek !== "*" && dayOfMonth === "*") {
      switch (parseInt(dayOfWeek)) {
        case 0:
          dayOfWeek = "on Sundays";
          break;
        case 1:
          dayOfWeek = "on Mondays";
          break;
        case 2:
          dayOfWeek = "on Tuesdays";
          break;
        case 3:
          dayOfWeek = "on Wednesdays";
          break;
        case 4:
          dayOfWeek = "on Thursdays";
          break;
        case 5:
          dayOfWeek = "on Fridays";
          break;
        case 6:
          dayOfWeek = "on Saturdays";
          break;
        default:
          cronToString =
            "Unreadable cron format. Cron will be displayed in its raw form: " +
            cronExpression;
          return cronToString;
      }
    }
    cronToString = cronToString + dayOfWeek + " ";
  }

  return cronToString;
}

问题

如何优化这段代码？

附加信息

• 这个方法是一个Vue.JS组件的一部分，所以如果我忘记将一些特定于Vue的内容翻译成，我很抱歉。
• 我还没有实现代码，以防管道在给定的一周/月天数上运行，而这些天数是以逗号分隔的一组数字提供的。

Answer 1

你做了很多测试。如果您实现了几个包含不同值的对象，并且只显示这些值，则会更简单。

您必须完成足够的对象来覆盖所有情况，但是这样可以将测试限制在最低限度。

例子：

// I won't print every cases but you got the idea
let dayOfWeekWhenNoMonthIsSpecified = {
    '*' : 'every day', '0' : 'on Sundays', '1' : 'on Mondays',
    '0,6' : 'on weekends', '1-5' : 'on weekdays'
};

cronToString = "Runs " + dayOfWeekWhenNoMonthIsSpecified[cron[4]];