Date.prototype.toLocaleDateString()

¥Syntax

toLocaleDateString()
toLocaleDateString(locales)
toLocaleDateString(locales, options)

¥Parameters

locales 和 options 参数自定义函数的行为，并让应用指定应使用其格式约定的语言。

¥The locales and options parameters customize the behavior of the function and let applications specify the language whose formatting conventions should be used.

在支持 Intl.DateTimeFormat API 的实现中，这些参数与 Intl.DateTimeFormat() 构造函数的参数完全对应。不支持 Intl.DateTimeFormat 的实现会被要求忽略这两个参数，从而使所使用的区域设置和返回的字符串形式完全依赖于实现。

¥In implementations that support the Intl.DateTimeFormat API, these parameters correspond exactly to the Intl.DateTimeFormat() constructor's parameters. Implementations without Intl.DateTimeFormat support are asked to ignore both parameters, making the locale used and the form of the string returned entirely implementation-dependent.

locales Optional

带有 BCP 47 语言标记的字符串，或此类字符串的数组。对应于 Intl.DateTimeFormat() 构造函数的 locales 参数。

在不支持 Intl.DateTimeFormat 的实现中，该参数被忽略，通常使用主机的区域设置。

options Optional

调整输出格式的对象。对应于 Intl.DateTimeFormat() 构造函数的 options 参数。timeStyle 选项必须未定义，否则将抛出 TypeError。如果 weekday、year、month 和 day 均未定义，则 year、month 和 day 将设置为 "numeric"。

在不支持 Intl.DateTimeFormat 的实现中，该参数被忽略。

有关这些参数及其使用方法的详细信息，请参阅 Intl.DateTimeFormat() constructor。

¥See the Intl.DateTimeFormat() constructor for details on these parameters and how to use them.

¥Return value

根据特定于语言的约定表示给定日期的日期部分的字符串。

¥A string representing the date portion of the given date according to language-specific conventions.

在 Intl.DateTimeFormat 的实现中，这相当于 new Intl.DateTimeFormat(locales, options).format(date)，其中 options 已按上述方式标准化。

¥In implementations with Intl.DateTimeFormat, this is equivalent to new Intl.DateTimeFormat(locales, options).format(date), where options has been normalized as described above.

注意：大多数时候，toLocaleDateString() 返回的格式是一致的。但是，即使在同一语言环境中，输出也可能因实现而异 - 输出变化是设计使然，并且规范允许。它也可能不是你所期望的。例如，字符串可以使用不间断空格或被双向控制字符包围。你不应该将 toLocaleDateString() 的结果与硬编码常量进行比较。

¥Note: Most of the time, the formatting returned by toLocaleDateString() is consistent. However, the output may vary between implementations, even within the same locale — output variations are by design and allowed by the specification. It may also not be what you expect. For example, the string may use non-breaking spaces or be surrounded by bidirectional control characters. You should not compare the results of toLocaleDateString() to hardcoded constants.

¥Examples

¥Using toLocaleDateString()

不指定 locale 的情况下使用此方法的基本用途会返回默认区域设置和默认选项的格式化字符串。

¥Basic use of this method without specifying a locale returns a formatted string in the default locale and with default options.

const date = new Date(Date.UTC(2012, 11, 12, 3, 0, 0));

// toLocaleDateString() without arguments depends on the implementation,
// the default locale, and the default time zone
console.log(date.toLocaleDateString());
// "12/11/2012" if run in en-US locale with time zone America/Los_Angeles

¥Checking for support for locales and options parameters

locales 和 options 参数可能并非在所有实现中都受支持，因为对国际化 API 的支持是可选的，并且某些系统可能没有必要的数据。对于没有国际化支持的实现，toLocaleDateString() 始终使用系统的区域设置，这可能不是你想要的。因为任何支持 locales 和 options 参数的实现都必须支持 Intl API，因此你可以检查后者是否存在以获取支持：

¥The locales and options parameters may not be supported in all implementations, because support for the internationalization API is optional, and some systems may not have the necessary data. For implementations without internationalization support, toLocaleDateString() always uses the system's locale, which may not be what you want. Because any implementation that supports the locales and options parameters must support the Intl API, you can check the existence of the latter for support:

function toLocaleDateStringSupportsLocales() {
  return (
    typeof Intl === "object" &&
    !!Intl &&
    typeof Intl.DateTimeFormat === "function"
  );
}

¥Using locales

此示例显示本地化日期格式的一些变化。为了获取应用用户界面中使用的语言的格式，请确保使用 locales 参数指定该语言（可能还有一些后备语言）：

¥This example shows some of the variations in localized date formats. In order to get the format of the language used in the user interface of your application, make sure to specify that language (and possibly some fallback languages) using the locales argument:

const date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

// formats below assume the local time zone of the locale;
// America/Los_Angeles for the US

// US English uses month-day-year order
console.log(date.toLocaleDateString("en-US"));
// "12/20/2012"

// British English uses day-month-year order
console.log(date.toLocaleDateString("en-GB"));
// "20/12/2012"

// Korean uses year-month-day order
console.log(date.toLocaleDateString("ko-KR"));
// "2012. 12. 20."

// Event for Persian, It's hard to manually convert date to Solar Hijri
console.log(date.toLocaleDateString("fa-IR"));
// "۱۳۹۱/۹/۳۰"

// Arabic in most Arabic speaking countries uses real Arabic digits
console.log(date.toLocaleDateString("ar-EG"));
// "٢٠‏/١٢‏/٢٠١٢"

// for Japanese, applications may want to use the Japanese calendar,
// where 2012 was the year 24 of the Heisei era
console.log(date.toLocaleDateString("ja-JP-u-ca-japanese"));
// "24/12/20"

// when requesting a language that may not be supported, such as
// Balinese, include a fallback language, in this case Indonesian
console.log(date.toLocaleDateString(["ban", "id"]));
// "20/12/2012"

¥Using options

可以使用 options 参数自定义 toLocaleDateString() 提供的结果：

¥The results provided by toLocaleDateString() can be customized using the options parameter:

const date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));

// Request a weekday along with a long date
const options = {
  weekday: "long",
  year: "numeric",
  month: "long",
  day: "numeric",
};
console.log(date.toLocaleDateString("de-DE", options));
// "Donnerstag, 20. Dezember 2012"

// An application may want to use UTC and make that visible
options.timeZone = "UTC";
options.timeZoneName = "short";
console.log(date.toLocaleDateString("en-US", options));
// "Thursday, December 20, 2012, UTC"

¥See also

• Intl.DateTimeFormat
• Date.prototype.toLocaleString()
• Date.prototype.toLocaleTimeString()
• Date.prototype.toString()