convert gmt to eastern time in javascript

To convert GMT to Eastern Time using JavaScript, you can use the built-in Date object and its related methods.

1. First, create a new Date object for the GMT time using new Date():

index.tsx
let gmtTime = new Date();
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2. Set the GMT time by passing a string with the appropriate date and time values, in ISO format (yyyy-mm-ddThh:mm:ssZ).

index.tsx
gmtTime.setUTCHours(15); // example of setting 3pm GMT
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3. Use the toLocaleString() method to convert the GMT time to the user’s local time zone, which will be the machine's timezone by default:

index.tsx
let estTime = new Date(gmtTime.toLocaleString());
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4. (optional) If you need to convert the estTime object to a specific time zone, you can set it using the setTimeZone method:

index.tsx
estTime.setTimeZone('America/New_York'); // set Eastern Time zone
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Here's the complete code snippet:

index.tsx
let gmtTime = new Date();
gmtTime.setUTCHours(15); // example of setting 3pm GMT
let estTime = new Date(gmtTime.toLocaleString());
estTime.setTimeZone('America/New_York'); // set Eastern Time zone

console.log('GMT Time: ' + gmtTime.toISOString()); // GMT Time: 2021-10-19T15:00:00.000Z
console.log('Eastern Time: ' + estTime.toLocaleString()); // Eastern Time: 10/19/2021, 11:00:00 AM
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Note: The Eastern Time zone uses daylight saving time, so you may need to adjust the code accordingly depending on the time of year.