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

To use the startOfWeek function from the date-fns library in a TypeScript project, follow these steps:

1. Install the date-fns library. You can use a package manager like npm or yarn.

npm install date-fns
# or
yarn add date-fns
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2. Import the startOfWeek function from the date-fns library.

import { startOfWeek } from 'date-fns';
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3. Use the startOfWeek function to get the start of the week for a given date. The function takes two arguments: a Date object and an optional options object.

const date = new Date();
const startOfWeekDate = startOfWeek(date); // default options: Monday as the first day of the week

console.log(startOfWeekDate); // will output the start of the week for the current date
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4. In some cases, TypeScript may not recognize the types of the date-fns functions, particularly if you're using an older version of the library. If you encounter this, you can create a type declaration file that adds the necessary types. Here's an example:

// date-fns.d.ts
declare module 'date-fns' {
  export function startOfWeek(
    date: Date | number | string,
    options?: { weekStartsOn: 0 | 1 | 2 | 3 | 4 | 5 | 6 }
  ): Date;
}
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With this declaration file in place, TypeScript should be able to infer the correct types for the startOfWeek function.