forked from lix-project/lix-website
44 lines
1.9 KiB
JavaScript
44 lines
1.9 KiB
JavaScript
'use strict';
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var GetIntrinsic = require('get-intrinsic');
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var $Date = GetIntrinsic('%Date%');
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var $TypeError = require('es-errors/type');
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var isInteger = require('../helpers/isInteger');
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var callBound = require('call-bind/callBound');
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var $indexOf = callBound('String.prototype.indexOf');
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var $slice = callBound('String.prototype.slice');
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var $toTimeString = callBound('Date.prototype.toTimeString');
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// https://262.ecma-international.org/14.0/#sec-timezoneestring
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module.exports = function TimeZoneString(tv) {
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if (!isInteger(tv)) {
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throw new $TypeError('Assertion failed: `tv` must be an integral Number');
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}
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// 1. Let localTimeZone be DefaultTimeZone().
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// 2. If IsTimeZoneOffsetString(localTimeZone) is true, then
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// a. Let offsetNs be ParseTimeZoneOffsetString(localTimeZone).
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// 3. Else,
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// a. Let offsetNs be GetNamedTimeZoneOffsetNanoseconds(localTimeZone, ℤ(ℝ(tv) × 106)).
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// 4. Let offset be 𝔽(truncate(offsetNs / 106)).
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// 5. If offset is +0𝔽 or offset > +0𝔽, then
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// a. Let offsetSign be "+".
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// b. Let absOffset be offset.
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// 6. Else,
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// a. Let offsetSign be "-".
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// b. Let absOffset be -offset.
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// 7. Let offsetMin be ToZeroPaddedDecimalString(ℝ(MinFromTime(absOffset)), 2).
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// 8. Let offsetHour be ToZeroPaddedDecimalString(ℝ(HourFromTime(absOffset)), 2).
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// 9. Let tzName be an implementation-defined string that is either the empty String or the string-concatenation of the code unit 0x0020 (SPACE), the code unit 0x0028 (LEFT PARENTHESIS), an implementation-defined timezone name, and the code unit 0x0029 (RIGHT PARENTHESIS).
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// 10. Return the string-concatenation of offsetSign, offsetHour, offsetMin, and tzName.
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// hack until DefaultTimeZone, IsTimeZoneOffsetString, ParseTimeZoneOffsetString, GetNamedTimeZoneOffsetNanoseconds, and "implementation-defined string" are available
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var ts = $toTimeString(new $Date(tv));
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return $slice(ts, $indexOf(ts, '(') + 1, $indexOf(ts, ')'));
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};
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