33 lines
1.0 KiB
JavaScript
33 lines
1.0 KiB
JavaScript
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import requiredArgs from "../_lib/requiredArgs/index.js";
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import getDay from "../getDay/index.js";
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import subDays from "../subDays/index.js";
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/**
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* @name previousDay
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* @category Weekday Helpers
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* @summary When is the previous day of the week?
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*
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* @description
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* When is the previous day of the week? 0-6 the day of the week, 0 represents Sunday.
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*
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* @param {Date | number} date - the date to check
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* @param {number} day - day of the week
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* @returns {Date} - the date is the previous day of week
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* @throws {TypeError} - 2 arguments required
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*
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* @example
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* // When is the previous Monday before Mar, 20, 2020?
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* const result = previousDay(new Date(2020, 2, 20), 1)
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* //=> Mon Mar 16 2020 00:00:00
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*
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* @example
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* // When is the previous Tuesday before Mar, 21, 2020?
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* const result = previousDay(new Date(2020, 2, 21), 2)
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* //=> Tue Mar 17 2020 00:00:00
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*/
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export default function previousDay(date, day) {
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requiredArgs(2, arguments);
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var delta = getDay(date) - day;
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if (delta <= 0) delta += 7;
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return subDays(date, delta);
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}
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