38 lines
1.1 KiB
JavaScript
38 lines
1.1 KiB
JavaScript
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import { getDay } from "./getDay.mjs";
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import { subDays } from "./subDays.mjs";
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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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* @typeParam DateType - The `Date` type, the function operates on. Gets inferred from passed arguments. Allows to use extensions like [`UTCDate`](https://github.com/date-fns/utc).
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*
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* @param date - The date to check
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* @param day - The day of the week
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*
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* @returns The date is the previous day of week
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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 function previousDay(date, day) {
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let 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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// Fallback for modularized imports:
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export default previousDay;
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