75 lines
2.3 KiB
JavaScript
75 lines
2.3 KiB
JavaScript
"use strict";
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exports.tzScan = tzScan;
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var _index = require("../tzOffset/index.cjs");
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/**
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* Time interval.
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*/
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/**
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* Time zone change record.
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*/
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/**
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* The function scans the time zone for changes in the given interval.
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*
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* @param timeZone - Time zone name (IANA or UTC offset)
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* @param interval - Time interval to scan for changes
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*
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* @returns Array of time zone changes
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*/
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function tzScan(timeZone, interval) {
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const changes = [];
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const monthDate = new Date(interval.start);
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monthDate.setUTCSeconds(0, 0);
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const endDate = new Date(interval.end);
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endDate.setUTCSeconds(0, 0);
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const endMonthTime = +endDate;
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let lastOffset = (0, _index.tzOffset)(timeZone, monthDate);
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while (+monthDate < endMonthTime) {
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// Month forward
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monthDate.setUTCMonth(monthDate.getUTCMonth() + 1);
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// Find the month where the offset changes
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const offset = (0, _index.tzOffset)(timeZone, monthDate);
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if (offset != lastOffset) {
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// Rewind a month back to find the day where the offset changes
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const dayDate = new Date(monthDate);
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dayDate.setUTCMonth(dayDate.getUTCMonth() - 1);
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const endDayTime = +monthDate;
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lastOffset = (0, _index.tzOffset)(timeZone, dayDate);
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while (+dayDate < endDayTime) {
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// Day forward
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dayDate.setUTCDate(dayDate.getUTCDate() + 1);
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// Find the day where the offset changes
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const offset = (0, _index.tzOffset)(timeZone, dayDate);
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if (offset != lastOffset) {
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// Rewind a day back to find the time where the offset changes
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const hourDate = new Date(dayDate);
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hourDate.setUTCDate(hourDate.getUTCDate() - 1);
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const endHourTime = +dayDate;
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lastOffset = (0, _index.tzOffset)(timeZone, hourDate);
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while (+hourDate < endHourTime) {
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// Hour forward
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hourDate.setUTCHours(hourDate.getUTCHours() + 1);
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// Find the hour where the offset changes
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const hourOffset = (0, _index.tzOffset)(timeZone, hourDate);
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if (hourOffset !== lastOffset) {
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changes.push({
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date: new Date(hourDate),
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change: hourOffset - lastOffset,
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offset: hourOffset
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});
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}
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lastOffset = hourOffset;
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}
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}
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lastOffset = offset;
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}
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}
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lastOffset = offset;
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}
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return changes;
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} |