If you run this JavaScript function on the 31st of a month, the result will be a month off. The best part is that this is the intended behvaior. JavaScript is a cursed language.

hh93

What would you expect “-1 month” to do for a date like 31st of March? Would the result be the same as for “-1 month” on 29th of March?

If you go back 2 months so the 31st is existing again - should that mean that the result of using -1 month twice should be different to using -2 months?

I think it’s just a stupid way to implement something like this as “month” isn’t a defined size so defining it with a fixed value and documenting it properly is a decent solution but noone should use that kind of function in the first place

☆ Yσɠƚԋσʂ ☆

This is literally how every sane API works in languages built by adults. For example, here’s what happens in Java:

java.time.LocalDate.of(2023, 3, 31)
> #object[java.time.LocalDate 0x2bc77260 "2023-03-31"]
java.time.LocalDate.of(2023, 3, 31).minusMonths(1)
> #object[java.time.LocalDate 0xac0dc15 "2023-02-28"]
java.time.LocalDate.of(2023, 3, 31).minusMonths(2)
> #object[java.time.LocalDate 0x44b9305f "2023-01-31"]

I have no idea where people get this notion that a month isn’t a defined size. Do people just not understand the concept of a month?

@mattreb@feddit.it

It is a stupid way to implement it, but the called function is named setMonth()! The minus one is performed externally, so if you set February you expect February, validation should adjust the other fields…

If you run this JavaScript function on the 31st of a month, the result will be a month off. The best part is that this is the intended behvaior. JavaScript is a cursed language.

If you run this JavaScript function on the 31st of a month, the result will be a month off. The best part is that this is the intended behvaior. JavaScript is a cursed language.

Programmer Humor

Rules: