day.js使用_使用Day.js解析，验证，处理和显示JavaScript中的日期和时间

迈不过友情╰ 2022-11-27 04:25 196阅读 0赞

day.js使用

With it’s last release nearly a year ago, the most recent commit over 6 months ago, and hundreds of open bugs and pull requests, it’s starting to seem like [Moment.js][] is slowing down and it’s time to shop for more actively maintained alternatives. Insert Day.js, a minimalist date and time library weighing in at 2kB that provides a mostly Moment.js-compatible API for ease of transition.

大约一年前的最新版本，六个月前的最新提交以及数百个打开的错误和提取请求，似乎开始使[Moment.js][]的速度变慢，是时候购买更积极维护的替代方案了。 插入Day.js，这是一个最小的日期和时间库，其大小为2kB，它提供了与Moment.js几乎兼容的API，以简化转换过程。

## Day.js入门 **(**Getting Started with Day.js**)** ##

To get started with Day.js in your Node.js project, simply add the dependency with either `npm` or `yarn`:

要在您的Node.js项目中开始使用Day.js，只需使用`npm`或`yarn`添加依赖项：

$ npm install dayjs --save
    # or
    $ yarn add dayjs

Then simply include it in your script:

然后只需将其包含在脚本中：

const dayjs = require('dayjs');

Day.js also works in modern browsers and can be self-hosted or included by way of a CDN provider like [cdnjs][].

Day.js也可以在现代浏览器中使用，并且可以自行托管，也可以通过CDN提供程序(例如[cdnjs)包含][cdnjs] 。

## 解析日期和时间 **(**Parsing Dates and Times**)** ##

Parsing a date and time string into a Day.js object is easy and supports strings, numbers, native JavaScript `Date` objects as well as other Day.js objects:

将日期和时间字符串解析为Day.js对象很容易，并且支持字符串，数字，本机JavaScript `Date`对象以及其他Day.js对象：

let date = dayjs('2019-12-27');
    date = dayjs('20191227');
    date = dayjs(new Date(2019, 11, 27));
    date = dayjs(day('2019-12-27'));

You can even omit the string entirely to default the Day.js object to the current date and time:

您甚至可以完全忽略该字符串，以将Day.js对象默认为当前日期和时间：

date = dayjs();

## 验证日期和时间 **(**Validating Dates and Times**)** ##

Once you’ve parsed a date and time with Day.js you can leverage the `isValid()` method to determine if what you passed in was actually something Day.js could parse:

使用Day.js解析日期和时间后，就可以利用`isValid()`方法来确定传入的内容是否实际上是Day.js可以解析的内容：

dayjs('2019-12-27').isValid(); // true
    dayjs('tomorrow').isValid(); // false

Additionally, if you were to attempt to display a Day.js object that was fed with a date that couldn’t be parsed, the return will be `Invalid Date`.

此外，如果您试图显示一个Day.js对象，该对象提供了无法解析的日期，则返回值为`Invalid Date` 。

## 显示日期和时间 **(**Displaying Dates and Times**)** ##

The `.format()` method allows us to take the Day.js object and convert it into a human-readable string. It supports your common set of date and time variables, like `YYYY` for a full year, and `MM` and `mm` for month and minutes respectively.

`.format()`方法允许我们获取Day.js对象并将其转换为人类可读的字符串。 它支持您常用的日期和时间变量集，例如，全年为`YYYY` ，月份和分钟为`MM`和`mm` 。

For those times when you want to include additional text that you don’t want to be converted to a date or time part, you can “hug” the string with brackets `[` and `]`:

对于那些当您想要包括不想被转换为日期或时间部分的其他文本时，可以用括号`[`和`]`来“拥抱”字符串：

dayjs().format('YYYY-MM-DD [at] HH:mm:ss');
    dayjs().format('HH:mm:ss [on] YYYY-MM-DD');

## 处理日期和时间 **(**Manipulating Dates and Times**)** ##

In a previous section we attempted to pass in the string `tomorrow` and it was considered an invalid date. To be able to get the date and time for tomorrow, we can start with today’s date and time, and add a day to it:

在上一节中，我们尝试`tomorrow`传递字符串，这被认为是无效日期。 为了能够获取明天的日期和时间，我们可以从今天的日期和时间开始，并为其添加一天：

dayjs().add(1, 'day').format('YYYY-MM-DD');

In addition to adding a `day`, you can also add `month` and `year` and even time-based intervals like `hour` and `minute`:

除了添加`day` ，您还可以添加`month`和`year` ，甚至是基于时间的时间间隔，例如`hour`和`minute` ：

dayjs().add(1, 'hour').format('YYYY-MM-DD HH:mm:ss');
    dayjs().add(30, 'minute').format('YYYY-MM-DD HH:mm:ss');
    dayjs().add(3, 'month').format('YYYY-MM-DD HH:mm:ss');
    dayjs().add(3, 'year').format('YYYY-MM-DD HH:mm:ss');

You can even chain it to do things like add multiple intervals:

您甚至可以将其链接起来以执行诸如添加多个间隔的操作：

dayjs().add(1, 'hour').add(30, 'minute').format('YYYY-MM-DD HH:mm:ss');

Don’t you worry, there’s a subtraction method as well:

不用担心，还有一种减法：

dayjs().subtract(4, 'hour').format('YYYY-MM-DD HH:mm:ss');

## 比较日期和时间 **(**Comparing Dates and Times**)** ##

One of the more complex tasks that comes up pretty regularly in development is the comparison of dates and times. Day.js makes it easy be providing helper methods such as `isBefore()` and `isAfter()`:

在开发中经常出现的比较复杂的任务之一是日期和时间的比较。 通过Day.js，可以轻松提供诸如`isBefore()`和`isAfter()`类的辅助方法：

## 结论 **(**Conclusion**)** ##

With it’s familiar interfacing and active maintenance (even during the holidays), Day.js seems like a great alternative for Moment.js.

有了熟悉的接口和主动维护(即使在假日期间)，Day.js似乎是Moment.js的绝佳替代品。

Give it a try on your next project, I know I will be.

试试看您的下一个项目，我知道我会的。

> 翻译自: [https://www.digitalocean.com/community/tutorials/js-dayjs][https_www.digitalocean.com_community_tutorials_js-dayjs]

day.js使用

[Moment.js]: https://www.digitalocean.com/community/tutorials/js-time-manipulations-momentjs
[cdnjs]: https://cdnjs.com/libraries/dayjs
[https_www.digitalocean.com_community_tutorials_js-dayjs]: https://www.digitalocean.com/community/tutorials/js-dayjs