convert hawaii time to gmt in typescript

index.ts
function convertToGMT(hawaiiDateTime: string): string {
  // create a new Date object for the input date/time string in Hawaiian Time
  const hawaiiDate = new Date(hawaiiDateTime + ' GMT-1000');

  // get the UTC time by adding the UTC offset for Hawaii Standard Time (UTC-10)
  const utcTime = new Date(hawaiiDate.getTime() + (hawaiiDate.getTimezoneOffset() * 60 * 1000) + (10 * 60 * 60 * 1000));

  // format the UTC time as a string in the desired format (e.g. YYYY-MM-DDTHH:mm:ssZ)
  const gmtDateTime = utcTime.toISOString();

  return gmtDateTime;
}
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index.ts
const hawaiiTime = '2021-06-22T12:30:00';
const gmtTime = convertToGMT(hawaiiTime);

console.log(gmtTime); // output: '2021-06-22T22:30:00.000Z'
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