获取已通过的时间，同时考虑用户的时区和时刻

Question

我正在React Native中做一个web应用程序，以显示事件列表。这些事件来自配置为GMT-4并位于America/Santo_Domingo的后端，即时区。

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

我的事件屏幕是这样的：

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

问题：当我执行new Date()进行计算时，一些设备报告不同的日期。这些日期有时差。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。我一直在遵循这个指南，我安装了时刻时区。

我将从后端收到的日期传递给这个函数：

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;
}

此功能处理转换：

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，但我有点困惑。

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

感谢您的帮助。

Answer 1

试试这个

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

Answer 2

function timeSince(date) {
var seconds = Math.floor((new Date() - date) / 1000);
var interval = seconds / 31536000;
if (interval > 1) {
return Math.floor(interval) + " " + formatMessage('Days');
}
interval = seconds / 2592000;
if (interval > 1) {
var days = (seconds % 2592000) / 86400;
return Math.floor(interval) + " " + formatMessage('Months') + formatMessage('And') + Math.floor(days) + " " + formatMessage('Days');
}
interval = seconds / 86400;
if (interval > 1) {
return Math.floor(interval) + " " + formatMessage('Days');
}
interval = seconds / 3600;
if (interval > 1) {
return Math.floor(interval) + " " + formatMessage('Hours');
}
interval = seconds / 60;
if (interval > 1) {
return Math.floor(interval) + " " + formatMessage('Minutes');
}
return Math.floor(seconds) + " " + formatMessage('Seconds');
}