How to use JS to write a method to determine whether the current time zone is daylight saving time

In front-end development, it may be more complicated to determine whether the current time zone is in daylight saving time, because the JavaScript standard library does not directly provide an API for detecting daylight saving time. However, you can make inferences by comparing local time with UTC time.

Daylight saving time usually means that local time is one hour faster than standard time. Therefore, you can tell whether the current daylight saving time is currently in daylight saving by comparing the difference between local time and UTC time. If the time difference is one hour longer than the time difference in non-daylight saving time, it is likely that it is daylight saving time.

Here is a simple JavaScript function to determine whether the current time zone may be in daylight saving time:

function isDaylightSavingTime() {
    // Get the UTC representation and local representation of the current time    const now = new Date();
    const januaryOffset = new Date((), 0, 1).getTimezoneOffset();
    const julyOffset = new Date((), 6, 1).getTimezoneOffset();
    const currentOffset = ();
    // If the time difference between January and July is different, it means that the area implements daylight saving time    if (januaryOffset !== julyOffset) {
        // If the current time difference is the same as that of July (the month when daylight saving time is usually effective), it is considered as daylight saving time        return currentOffset === julyOffset;
    }
    // If there is no daylight saving time change, return false    return false;
}
(isDaylightSavingTime() ? "It's daylight saving time" : "It's not daylight saving time");

Note: This method is not 100% accurate, as it relies on time zone offsets in different months of the year to determine whether there is daylight saving time. In some areas, the rules of daylight saving time may be more complex or may change at any time. Additionally, some areas may not follow standard daylight saving time adjustment rules.

If you need more precise daylight saving time detection, you may need to use a third-party library such asCooperate with itmoment-timezonePlugins, these libraries provide more comprehensive time zone support.

useandmoment-timezoneExample:

// First, make sure you have introduced andconst moment = require('moment-timezone');
function isDaylightSavingTimeWithMoment() {
    const now = moment();
    const timezone = (); // Guess the current time zone    const isDST = (now, timezone).isDST(); // Determine whether it is in the daylight saving time    return isDST;
}
(isDaylightSavingTimeWithMoment() ? "It's daylight saving time" : "It's not daylight saving time");

This method utilizesmoment-timezoneThe powerful function of the library can more accurately determine whether it is currently in daylight saving time.

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