51 lines
1.6 KiB
TypeScript
51 lines
1.6 KiB
TypeScript
export function billingPeriod(billingDay: number, date: Date) {
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// Determine the anchor month and year
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let anchorMonth, anchorYear
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if (date.getDate() >= billingDay) {
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anchorMonth = date.getMonth() + 1 // JavaScript months are 0-11
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anchorYear = date.getFullYear()
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} else {
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// Move to previous month
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if (date.getMonth() === 0) {
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// January
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anchorMonth = 12
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anchorYear = date.getFullYear() - 1
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} else {
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anchorMonth = date.getMonth() // No +1 because we're going backwards
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anchorYear = date.getFullYear()
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}
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}
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// Calculate start date
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const lastDayOfMonth = new Date(anchorYear, anchorMonth, 0).getDate()
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const startDay = Math.min(billingDay, lastDayOfMonth)
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const startDate = new Date(anchorYear, anchorMonth - 1, startDay) // -1 because JS months are 0-based
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// Calculate next month and year
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let nextMonth, nextYear
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if (anchorMonth === 12) {
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nextMonth = 1
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nextYear = anchorYear + 1
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} else {
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nextMonth = anchorMonth + 1
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nextYear = anchorYear
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}
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// Calculate end date
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const nextLastDayOfMonth = new Date(nextYear, nextMonth, 0).getDate()
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const endDay = Math.min(billingDay, nextLastDayOfMonth)
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const endDate = new Date(nextYear, nextMonth - 1, endDay)
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endDate.setDate(endDate.getDate() - 1) // Subtract one day
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return [startDate, endDate]
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}
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export function formatDate(date = new Date()) {
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const year = date.getFullYear()
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const month = String(date.getMonth() + 1).padStart(2, '0') // e.g: January = 01
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const day = String(date.getDate()).padStart(2, '0')
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return `${year}-${month}-${day}`
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}
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