53 lines
1.6 KiB
JavaScript
53 lines
1.6 KiB
JavaScript
import { getDate } from "./getDate.mjs";
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import { getDay } from "./getDay.mjs";
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import { startOfMonth } from "./startOfMonth.mjs";
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import { getDefaultOptions } from "./_lib/defaultOptions.mjs";
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/**
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* The {@link getWeekOfMonth} function options.
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*/
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/**
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* @name getWeekOfMonth
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* @category Week Helpers
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* @summary Get the week of the month of the given date.
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*
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* @description
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* Get the week of the month of the given date.
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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 given date
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* @param options - An object with options.
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*
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* @returns The week of month
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*
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* @example
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* // Which week of the month is 9 November 2017?
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* const result = getWeekOfMonth(new Date(2017, 10, 9))
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* //=> 2
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*/
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export function getWeekOfMonth(date, options) {
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const defaultOptions = getDefaultOptions();
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const weekStartsOn =
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options?.weekStartsOn ??
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options?.locale?.options?.weekStartsOn ??
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defaultOptions.weekStartsOn ??
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defaultOptions.locale?.options?.weekStartsOn ??
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0;
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const currentDayOfMonth = getDate(date);
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if (isNaN(currentDayOfMonth)) return NaN;
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const startWeekDay = getDay(startOfMonth(date));
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let lastDayOfFirstWeek = weekStartsOn - startWeekDay;
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if (lastDayOfFirstWeek <= 0) lastDayOfFirstWeek += 7;
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const remainingDaysAfterFirstWeek = currentDayOfMonth - lastDayOfFirstWeek;
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return Math.ceil(remainingDaysAfterFirstWeek / 7) + 1;
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}
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// Fallback for modularized imports:
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export default getWeekOfMonth;
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