how to use the differenceincalendardays function from the date-fns library in typescript

To use the differenceInCalendarDays function from the date-fns library in TypeScript, you need to first install the library using npm or yarn.

index.ts
npm install date-fns
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or

index.ts
yarn add date-fns
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Once installed, you can import the function and use it in your code as follows:

index.ts
import { differenceInCalendarDays } from 'date-fns';

const date1 = new Date('2021-01-01');
const date2 = new Date('2021-01-10');

const difference = differenceInCalendarDays(date2, date1);

console.log(difference); // Output: 9
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In this example, we import the differenceInCalendarDays function from the date-fns library. We then create two Date objects representing January 1st and January 10th, 2021. We pass these dates to the differenceInCalendarDays function, which calculates the number of calendar days between the two dates (excluding the time component). We then log the output, which is 9.

Note that differenceInCalendarDays returns an integer value representing the number of whole days between the two dates, with any partial days (e.g. due to daylight saving time changes) rounded towards zero. If the second date is before the first date, the result will be negative.