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

To use the isValid function from the date-fns library in TypeScript, you need to install the library and its types:

index.ts
npm install date-fns
npm install -D @types/date-fns
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Then, you can import the function and use it like this:

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

const date = new Date('2021-01-01');
const isValidDate = isValid(date); // returns true
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The isValid function checks if a given date is valid, i.e. if it represents a real calendar date. If the date is valid, it returns true, otherwise it returns false.

You can also pass a second argument to the function to specify additional options:

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

const date = new Date('2021-02-30');
const isValidDate = isValid(date, { strict: true }); // returns false because February 30th is not a valid date
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In this example, we pass an additional option { strict: true } to the isValid function. This tells the function to perform a strict validation, which means that it will not accept non-existing dates like February 30th.