获取已经过去的时间，考虑到用户的TimeZone with Moment

Question

我正在用 React Native 开发一个 Web 应用程序来显示事件列表。这些事件来自配置为 GMT -4 且位于 America/Santo_Domingo 的后端，作为时区。

我从后端收到的事件日期是 2020-11-05T16:02:13.1018115。

我的活动画面是这样的：

Title: Hi, a party has started!
Description: 1 hour ago // <= could be year, month, day, hour, minute or second

问题： 当我new Date() 进行计算时，一些设备报告不同的日期。这些日期有几个小时的差异。例如，使用时区 America/La_Paz 或 Etc/GMT+12.

的设备

我的结论是我需要考虑设备的时区来进行计算。我正在关注 this guide and I have installed Moment Timezone。

我将从后端收到的日期传递给此函数：

 export const timeSince = (backEndTimeStamp) => {

   // get device timezone eg. -> "America/La_Paz"
   const deviceTimeZone = 'America/La_Paz';

   // Make moment of right now, using the device timezone
   const today = moment().tz(deviceTimeZone);

   // Get the UTC offset in hours
   const currentTimeZoneOffsetInHours = today.utcOffset() / 60;

   const convertedToLocalTime = formatTimeByOffset(backEndTimeStamp, currentTimeZoneOffsetInHours);

   const years = today.diff(convertedToLocalTime, 'years');
   const months = today.diff(convertedToLocalTime, 'months');
   const days = today.diff(convertedToLocalTime, 'days');
   const hours = today.diff(convertedToLocalTime, 'hours');
   const minutes = today.diff(convertedToLocalTime, 'minutes');
   const seconds = today.diff(convertedToLocalTime, 'seconds');

   let timeDiff = '';
   if (years > 0) {
     timeDiff = years + (years === 1 ? ' year' : ' years');
   } else if (months > 0) {
     timeDiff = months + (months === 1 ? ' month' : ' months');
   } else if (days > 0) {
     timeDiff = days + (days === 1 ? ' day' : ' days');
   } else if (hours > 0) {
     timeDiff = hours + (hours === 1 ? ' hour' : ' hours');
   } else if (minutes > 0) {
     timeDiff = minutes + (minutes === 1 ? ' minute' : ' minutes');
   } else if (seconds > 0) {
     timeDiff = seconds + (seconds === 1 ? ' second' : ' seconds');
   } else {
     timeDiff = 'unknown';
   }

   return timeDiff;
  }

此函数处理转换：

export const formatTimeByOffset = (dateString, offset) => {
  // Params:
  // How the backend sends me a timestamp
  // dateString: on the form yyyy-mm-dd hh:mm:ss
  // offset: the amount of hours to add.

  // If we pass anything falsy return empty string
  if (!dateString) return '';
  if (dateString.length === 0) return '';

  // Step 1: Parse the backend date string

  // Get Parameters needed to create a new date object
  const year = dateString.slice(0, 4);
  const month = dateString.slice(5, 7);
  const day = dateString.slice(8, 10);
  const hour = dateString.slice(11, 13);
  const minute = dateString.slice(14, 16);
  const second = dateString.slice(17, 19);

  // Step: 2 Make a JS date object with the data
  const dateObject = new Date(`${year}-${month}-${day}T${hour}:${minute}:${second}`);

  // Step 3: Get the current hours from the object
  const currentHours = dateObject.getHours();

  // Step 4: Add the offset to the date object
  dateObject.setHours(currentHours + offset);

  // Step 5: stringify the date object, replace the T with a space and slice off the seconds.
  const newDateString = dateObject
    .toISOString()
    .replace('T', ' ')
    .slice(0, 19);

  // Step 6: Return the new formatted date string with the added offset
  return `${newDateString}`;
}

一些用户看到 1-4 小时之间的差异。

示例：

Today: Thu Nov 05 2020 19:0803 GMT-0400
Date from backend: 2020-11-05T16:27:40.687
Date converted to local time using the function above: 2020-11-05 12:27:40
Result: 6 hours // <= Has an extra hour

我尝试了很多东西，我有点困惑。

我的目标是获取已经过去的时间，同时考虑到用户的时区。知道后端使用 GMT -4 向我发送日期。

感谢任何帮助。

Answer 1

试试这个

var localTime = moment.utc("2020-11-05T16:02:13.1018115").add(4, 'hour').local().fromNow();

获取已经过去的时间，考虑到用户的TimeZone with Moment

Get the time that has been passed, taking into account the user's TimeZone with Moment

javascript

moment-timezone