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index.js
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index.js
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var MILLISECONDS_IN_MINUTE = 60000
/**
* Google Chrome as of 67.0.3396.87 introduced timezones with offset that includes seconds.
* They usually appear for dates that denote time before the timezones were introduced
* (e.g. for 'Europe/Prague' timezone the offset is GMT+00:57:44 before 1 October 1891
* and GMT+01:00:00 after that date)
*
* Date#getTimezoneOffset returns the offset in minutes and would return 57 for the example above,
* which would lead to incorrect calculations.
*
* This function returns the timezone offset in milliseconds that takes seconds in account.
*/
export default function getTimezoneOffsetInMilliseconds (dirtyDate) {
var date = new Date(dirtyDate.getTime())
var baseTimezoneOffset = date.getTimezoneOffset()
date.setSeconds(0, 0)
var millisecondsPartOfTimezoneOffset = date.getTime() % MILLISECONDS_IN_MINUTE
return baseTimezoneOffset * MILLISECONDS_IN_MINUTE + millisecondsPartOfTimezoneOffset
}