date-diff.ts
· 1.4 KiB · TypeScript
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const calcDateDifference = (
start: string | Date,
end: string | Date,
): { year: number; month: number; day: number } => {
// Convert to true dates without time
let startDate = new Date(new Date(start).toISOString().substring(0, 10));
let endDate = new Date(
(end ? new Date(end) : new Date()).toISOString().substring(0, 10),
);
// If start date comes after end, flip them around
if (startDate > endDate) {
const swap = startDate;
startDate = endDate;
endDate = swap;
}
// Account for leap years
const startYear = startDate.getFullYear();
const february =
(startYear % 4 === 0 && startYear % 100 !== 0) || startYear % 400 === 0
? 29
: 28;
const daysInMonth = [31, february, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
// Create year and month diffs
let yearDiff = endDate.getFullYear() - startYear;
let monthDiff = endDate.getMonth() - startDate.getMonth();
if (monthDiff < 0) {
yearDiff--;
monthDiff += 12;
}
// Create day diff while adjusting others
let dayDiff = endDate.getDate() - startDate.getDate();
if (dayDiff < 0) {
if (monthDiff > 0) {
monthDiff--;
} else {
yearDiff--;
monthDiff = 11;
}
dayDiff += daysInMonth[startDate.getMonth()];
}
// Return true differentials
return {
year: yearDiff,
month: monthDiff,
day: dayDiff,
};
}
| 1 | const calcDateDifference = ( |
| 2 | start: string | Date, |
| 3 | end: string | Date, |
| 4 | ): { year: number; month: number; day: number } => { |
| 5 | // Convert to true dates without time |
| 6 | let startDate = new Date(new Date(start).toISOString().substring(0, 10)); |
| 7 | let endDate = new Date( |
| 8 | (end ? new Date(end) : new Date()).toISOString().substring(0, 10), |
| 9 | ); |
| 10 | |
| 11 | // If start date comes after end, flip them around |
| 12 | if (startDate > endDate) { |
| 13 | const swap = startDate; |
| 14 | startDate = endDate; |
| 15 | endDate = swap; |
| 16 | } |
| 17 | |
| 18 | // Account for leap years |
| 19 | const startYear = startDate.getFullYear(); |
| 20 | const february = |
| 21 | (startYear % 4 === 0 && startYear % 100 !== 0) || startYear % 400 === 0 |
| 22 | ? 29 |
| 23 | : 28; |
| 24 | const daysInMonth = [31, february, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]; |
| 25 | |
| 26 | // Create year and month diffs |
| 27 | let yearDiff = endDate.getFullYear() - startYear; |
| 28 | let monthDiff = endDate.getMonth() - startDate.getMonth(); |
| 29 | if (monthDiff < 0) { |
| 30 | yearDiff--; |
| 31 | monthDiff += 12; |
| 32 | } |
| 33 | |
| 34 | // Create day diff while adjusting others |
| 35 | let dayDiff = endDate.getDate() - startDate.getDate(); |
| 36 | if (dayDiff < 0) { |
| 37 | if (monthDiff > 0) { |
| 38 | monthDiff--; |
| 39 | } else { |
| 40 | yearDiff--; |
| 41 | monthDiff = 11; |
| 42 | } |
| 43 | dayDiff += daysInMonth[startDate.getMonth()]; |
| 44 | } |
| 45 | |
| 46 | // Return true differentials |
| 47 | return { |
| 48 | year: yearDiff, |
| 49 | month: monthDiff, |
| 50 | day: dayDiff, |
| 51 | }; |
| 52 | } |
| 53 |