39 lines
1.8 KiB
JavaScript
39 lines
1.8 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 isNaN = require('../helpers/isNaN');
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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/12.0/#sec-timezoneestring
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module.exports = function TimeZoneString(tv) {
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if (typeof tv !== 'number' || isNaN(tv)) {
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throw new $TypeError('Assertion failed: `tv` must be a non-NaN Number'); // steps 1 - 2
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}
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// 3. Let offset be LocalTZA(tv, true).
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// 4. If offset ≥ +0𝔽, then
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// a. Let offsetSign be "+".
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// b. Let absOffset be offset.
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// 5. Else,
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// a. Let offsetSign be "-".
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// b. Let absOffset be -offset.
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// 6. Let offsetMin be the String representation of MinFromTime(absOffset), formatted as a two-digit decimal number, padded to the left with the code unit 0x0030 (DIGIT ZERO) if necessary.
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// 7. Let offsetHour be the String representation of HourFromTime(absOffset), formatted as a two-digit decimal number, padded to the left with the code unit 0x0030 (DIGIT ZERO) if necessary.
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// 8. 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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// 9. Return the string-concatenation of offsetSign, offsetHour, offsetMin, and tzName.
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// hack until LocalTZA, 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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