使用日期

¥Working With Dates

以下是如何使用 Mongoose 结构声明 Date 类型的路径：

¥Here's how you declare a path of type Date with a Mongoose schema:

const mongoose = require('mongoose');

const userSchema = new mongoose.Schema({
  name: String,
  // `lastActiveAt` is a date
  lastActiveAt: Date
});
const User = mongoose.model('User', userSchema);

当你创建用户 document 时，Mongoose 会使用 Date() 构造函数 将值转换为 原生 JavaScript 日期。

¥When you create a user document, Mongoose will cast the value to a native JavaScript date using the Date() constructor.

const user = new User({
  name: 'Jean-Luc Picard',
  lastActiveAt: '2002-12-09'
});
user.lastActiveAt instanceof Date; // true

当你 验证文档 时，无效日期将导致 CastError。

¥An invalid date will lead to a CastError when you validate the document.

const user = new User({
  name: 'Jean-Luc Picard',
  lastActiveAt: 'not a date'
});
user.lastActiveAt instanceof Date; // false
user.validateSync().errors['lastActiveAt']; // CastError

验证器

¥Validators

日期有两个内置验证器：min 和 max。如果给定日期严格小于 min 或严格大于 max，这些验证器将报告 ValidatorError。

¥Dates have two built-in validators: min and max. These validators will report a ValidatorError if the given date is strictly less than min or strictly greater than max.

const episodeSchema = new mongoose.Schema({
  title: String,
  airedAt: {
    type: Date,
    // The dates of the first and last episodes of
    // Star Trek: The Next Generation
    min: '1987-09-28',
    max: '1994-05-23'
  }
});
const Episode = mongoose.model('Episode', episodeSchema);

const ok = new Episode({
  title: 'Encounter at Farpoint',
  airedAt: '1987-09-28'
});
ok.validateSync(); // No error

const bad = new Episode({
  title: 'What You Leave Behind',
  airedAt: '1999-06-02'
});
bad.airedAt; // "1999-06-02T00:00:00.000Z"

// Path `airedAt` (Tue Jun 01 1999 20:00:00 GMT-0400 (EDT)) is after
// maximum allowed value (Sun May 22 1994 20:00:00 GMT-0400 (EDT)).
bad.validateSync();

查询

¥Querying

MongoDB 支持按日期范围查询和按日期排序。以下是按日期、日期范围查询和按日期排序的一些示例：

¥MongoDB supports querying by date ranges and sorting by dates. Here's some examples of querying by dates, date ranges, and sorting by date:

// Find episodes that aired on this exact date
return Episode.find({ airedAt: new Date('1987-10-26') }).
  then(episodes => {
    episodes[0].title; // "Where No One Has Gone Before"
    // Find episodes within a range of dates, sorted by date ascending
    return Episode.
      find({ airedAt: { $gte: '1987-10-19', $lte: '1987-10-26' } }).
      sort({ airedAt: 1 });
  }).
  then(episodes => {
    episodes[0].title; // "The Last Outpost"
    episodes[1].title; // "Where No One Has Gone Before"
  });

铸造边缘案例

¥Casting Edge Cases

日期转换有一些与 JavaScript 原生日期解析不同的小情况。首先，Mongoose 在给定对象上查找 valueOf() 功能，并在转换日期之前调用 valueOf()。这意味着 Mongoose 可以自动将 矩对象 转换为日期。

¥Date casting has a couple small cases where it differs from JavaScript's native date parsing. First, Mongoose looks for a valueOf() function on the given object, and calls valueOf() before casting the date. This means Mongoose can cast moment objects to dates automatically.

const moment = require('moment');
const user = new User({
  name: 'Jean-Luc Picard',
  lastActiveAt: moment.utc('2002-12-09')
});
user.lastActiveAt; // "2002-12-09T00:00:00.000Z"

默认情况下，如果将数字字符串传递给 Date 构造函数，JavaScript 将尝试将其转换为年份。

¥By default, if you pass a numeric string to the Date constructor, JavaScript will attempt to convert it to a year.

new Date(1552261496289); // "2019-03-10T23:44:56.289Z"
new Date('1552261496289'); // "Invalid Date"
new Date('2010'); // 2010-01-01T00:00:00.000Z

Mongoose 转换包含 JavaScript 中可表示日期的范围 之外的数字的数字字符串，并将其转换为数字，然后将其传递给日期构造函数。

¥Mongoose converts numeric strings that contain numbers outside the range of representable dates in JavaScript and converts them to numbers before passing them to the date constructor.

[require: Date Tutorial.*Example 1.4.3]

时区

¥Timezones

MongoDB 将日期存储为 64 位整数，表示 Mongoose 默认不存储时区信息。当你调用 Date#toString() 时，JavaScript 运行时将使用 你操作系统的时区。

¥MongoDB stores dates as 64-bit integers, which means that Mongoose does not store timezone information by default. When you call Date#toString(), the JavaScript runtime will use your OS' timezone.