mirror of
https://github.com/jbranchaud/til
synced 2026-01-03 07:08:01 +00:00
37 lines
708 B
Markdown
37 lines
708 B
Markdown
# New Dates Can Take Out Of Bounds Values
|
|
|
|
You can create a new date by feeding it arguments for _year_, _month_, and
|
|
_day_.
|
|
|
|
```javascript
|
|
> new Date(2017, 11, 31)
|
|
Sun Dec 31 2017 00:00:00 GMT-0600 (CST)
|
|
```
|
|
|
|
What happens if we push the _day_ value out of bounds?
|
|
|
|
```javascript
|
|
> new Date(2017, 11, 32)
|
|
Mon Jan 01 2018 00:00:00 GMT-0600 (CST)
|
|
```
|
|
|
|
It rolls over to the next month.
|
|
|
|
Does the same happen when we push the _month_ value out of bounds?
|
|
|
|
```javascript
|
|
> new Date(2017, 12, 31)
|
|
Wed Jan 31 2018 00:00:00 GMT-0600 (CST)
|
|
```
|
|
|
|
Yep.
|
|
|
|
What about negative values?
|
|
|
|
```javascript
|
|
> new Date(2018, -1, 31)
|
|
Sun Dec 31 2017 00:00:00 GMT-0600 (CST)
|
|
```
|
|
|
|
It rolls the month, and consequently the year, back.
|