Temporal.Instant.prototype.toLocaleString()
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
The toLocaleString() method of Temporal.Instant instances returns a string with a language-sensitive representation of this instant. In implementations with Intl.DateTimeFormat API support, this method delegates to Intl.DateTimeFormat.
Every time toLocaleString is called, it has to perform a search in a big database of localization strings, which is potentially inefficient. When the method is called many times with the same arguments, it is better to create an Intl.DateTimeFormat object and use its format() method, because a DateTimeFormat object remembers the arguments passed to it and may decide to cache a slice of the database, so future format calls can search for localization strings within a more constrained context.
Syntax
toLocaleString()
toLocaleString(locales)
toLocaleString(locales, options)
Parameters
The locales and options parameters customize the behavior of the function and let applications specify the language whose formatting conventions should be used.
In implementations that support the Intl.DateTimeFormat API, these parameters correspond exactly to the Intl.DateTimeFormat() constructor's parameters. Implementations without Intl.DateTimeFormat support return the exact same string as toString(), ignoring both parameters.
localesOptional-
A string with a BCP 47 language tag, or an array of such strings. Corresponds to the
localesparameter of theIntl.DateTimeFormat()constructor. optionsOptional-
An object adjusting the output format. Corresponds to the
optionsparameter of theIntl.DateTimeFormat()constructor.
See the Intl.DateTimeFormat() constructor for details on these parameters and how to use them.
Return value
A string representing the given instant according to language-specific conventions.
In implementations with Intl.DateTimeFormat, this is equivalent to new Intl.DateTimeFormat(locales, options).format(instant).
Note:
Most of the time, the formatting returned by toLocaleString() 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 toLocaleString() to hardcoded constants.
Examples
Using toLocaleString()
Basic use of this method without specifying a locale returns a formatted string in the default locale and with default options.
const instant = Temporal.Instant.from("2021-08-01T12:34:56Z");
console.log(instant.toLocaleString()); // 8/1/2021, 12:34:56 AM (assuming en-US locale and device in UTC time zone)
Specifications
| Specification |
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| Temporal # sec-temporal.instant.prototype.tolocalestring |
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Legend
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- Full support
- Full support
- In development. Supported in a pre-release version.
- In development. Supported in a pre-release version.
- No support
- No support
- See implementation notes.