how to use the milliseconds function from date-fns in javascript

To use the milliseconds function from the date-fns library in JavaScript, you first need to install the library by running the following command in your terminal:

index.tsx
npm install date-fns
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Once you have installed the library, you can import the milliseconds function into your code using the following code snippet:

index.tsx
// Import the milliseconds function from date-fns
import { milliseconds } from 'date-fns';

// Get the number of milliseconds for a specified time
const time = '12:30:15';
const millisecondsValue = milliseconds(`1970-01-01T${time}Z`);
console.log(millisecondsValue); // Output: 45015000
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In the above code snippet, we imported the milliseconds function from the date-fns library and used it to convert a specified time into the number of milliseconds since the Unix epoch (January 1st, 1970 at 00:00:00 UTC). We passed the time value to the milliseconds function along with a date string that corresponds to the Unix epoch. The returned value is the number of milliseconds for the specified time.

The milliseconds function can also be used to convert a date object to the number of milliseconds since the Unix epoch. For example:

index.tsx
// Convert a date object to milliseconds
const date = new Date('2021-08-17T12:30:15');
const millisecondsValue = milliseconds(date);
console.log(millisecondsValue); // Output: 1629213015000
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In the above code snippet, we created a Date object and passed it to the milliseconds function. The returned value is the number of milliseconds since the Unix epoch for the specified date.

The milliseconds function can also be used for formatting durations in milliseconds into a time format.