toLocaleTimeString() method of
Date instances returns a string with a language-sensitive representation of the time portion of this date in the local timezone. In implementations with
Intl.DateTimeFormat API support, this method simply calls
toLocaleTimeString 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 a
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.