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

To use the differenceInCalendarISOWeeks function from the date-fns library in TypeScript, you need to install the date-fns package using a package manager like npm or yarn. Then, you can import the function and use it in your TypeScript code like this:

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

const date1 = new Date(2019, 0, 1); // January 1, 2019
const date2 = new Date(2021, 0, 1); // January 1, 2021

const difference = differenceInCalendarISOWeeks(date1, date2);
console.log(difference); // Outputs: 104
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In this example, we first import the differenceInCalendarISOWeeks function from the date-fns package. We then create two Date objects representing January 1st, 2019 and January 1st, 2021, respectively.

Finally, we call the differenceInCalendarISOWeeks function with the two dates as arguments, and assign the result to the difference variable. We then log the value of difference to the console, which should output 104.

Note that the differenceInCalendarISOWeeks function calculates the difference between two dates in terms of calendar ISO weeks, which are defined as 7-day periods starting on Monday and ending on Sunday.