# Automatic date adjustment in JavaScript

JavaScript has a very interesting and useful feature: if an incorrect point in time was specified when creating the `Date` object, it will automatically be recalculated to the correct one. Let's look at an example.

As you know, there is no date of January `35`th. The maximum possible day in January is `31`. It turns out that our date January `35` has `4` extra days. JavaScript in this case will simply add those extra `4` days to the next month:

`let date = new Date(2018, 0, 35); console.log(date); // will be February 4th`

You can specify not only extra days, but also months. It should be remembered that months start from zero, which means that the last valid month is `11`th. If you specify `12`th month, you get January of the next year:

`let date = new Date(2018, 12, 1); // indicates the 12th month console.log(date); // shows January 1, 2019`

The described adjustment also works in a smaller direction. As you know, the smallest day of the month is the day numbered `1`. Therefore, if you specify a day with the number `0`, then you get the last day of the previous month:

`let date = new Date(2018, 1, 0); // sets zero day console.log(date); // will be January 31st`

You can also specify negative days and months. It must be remembered that the minimum day has the number `1`, and the minimum month has the number `0`. This means that minus the first day falls on `2`d day since the end of the previous month, and minus the first month just falls on the last month of the previous year:

`let date = new Date(2018, 1, -1); // sets -1 day console.log(date); // will be January 30th`
`let date = new Date(2018, -1, 1); // sets -1 month console.log(date); // shows December 1, 2017`

All of the above works similarly with hours, minutes and seconds:

`let date = new Date(2018, 0, 1, 24, 0, 0); // indicates the 24th hour console.log(date); // will be January 2nd, 0 hours`
`let date = new Date(2018, 0, 1, 25, 0, 0); // indicates the 25th hour console.log(date); // will be January 2nd, 1 hour`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 1, 35); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 15, 1); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 3, 31); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 1, 31); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 12, 33); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 33, 33); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 5, 0); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 0, 0); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, -12, -33); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 0, 1, 23, 0, 60); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 0, 1, 23, 60, 0); console.log(date); // what will be the date?`

Determine what date JavaScript will convert the next point in time to:

`let date = new Date(2018, 0, 1, 100, 100, 100); console.log(date); // what will be the date?`
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