4 ms·

Any operation like adding/substracting months from a date is very messy to implement yourself. What is one month ago when you are March, 31st? We have to deal

by forty 4y ago

Any operation like adding/substracting months from a date is very messy to implement yourself. What is one month ago when you are March, 31st? We have to deal with monthly subscriptions and it's not fun.

TekMol 4y ago
First you have to define what you mean by "one month ago". Is it 30 days ago? Or last month? Or a certain number of milliseconds ago? No library can help you with that. You have to define what you actually want to calculate.
- 9wzYQbTYsAIc 4y ago
  At some point you will need to calculate how many leap years to account for and whether or not a leap second was introduced in between two arbitrary times. Time libraries can help you with that.
  - forty 4y ago
    Exactly there is the same problem, to a lesser extend, when adding/subtracting years which is not trivial to do properly.
    - 9wzYQbTYsAIc 4y ago
      Let alone determining requirements for thresholds. This discussion reminds me of this bug report: https://bugzilla.mozilla.org/show_bug.cgi?id=1715455 https://bugzilla.mozilla.org/show_bug.cgi?id=1715455
    - ponyous 4y ago
      Why can’t you use Date.getFullYear with setFullYear?
- forty 4y ago
  Absolutely. moment has a definition of that and compute it in a consistent way, which is useful. But if you want to come up with a different definition then it cannot help you indeed.
throwaway0x7E6 4y ago
>What is one month ago when you are March, 31st? "one month ago" is between "a few weeks ago" and "a few months ago". >We have to deal with monthly subscriptions and it's not fun. it is a lot less unfun if you define a month as N calendar days in your terms of service, like virtually everyone does
- forty 4y ago
  Yes, that's what we do mostly, except to track external subscriptions that actually use months (I believe the Google playstore does that but I could be mistaken with another service)
- inopinatus 4y ago
  And they would be guilty of misleading the consumer when doing so, and possibly accounting fraud as well because neither GAAP nor IFRS recognise such a calendar; the closest available is the 4-4-5 standard. This is why we don’t let engineers write contracts. Many seem to think that law is a programming language in which they can redefine reality. It ain’t.

by forty 4y ago

TekMol 4y ago

First you have to define what you mean by "one month ago". Is it 30 days ago? Or last month? Or a certain number of milliseconds ago? No library can help you with that. You have to define what you actually want to calculate.

9wzYQbTYsAIc 4y ago
At some point you will need to calculate how many leap years to account for and whether or not a leap second was introduced in between two arbitrary times. Time libraries can help you with that.
- forty 4y ago
  Exactly there is the same problem, to a lesser extend, when adding/subtracting years which is not trivial to do properly.
  - 9wzYQbTYsAIc 4y ago
    Let alone determining requirements for thresholds. This discussion reminds me of this bug report: https://bugzilla.mozilla.org/show_bug.cgi?id=1715455 https://bugzilla.mozilla.org/show_bug.cgi?id=1715455
  - ponyous 4y ago
    Why can’t you use Date.getFullYear with setFullYear?
forty 4y ago
Absolutely. moment has a definition of that and compute it in a consistent way, which is useful. But if you want to come up with a different definition then it cannot help you indeed.

throwaway0x7E6 4y ago

>What is one month ago when you are March, 31st? "one month ago" is between "a few weeks ago" and "a few months ago". >We have to deal with monthly subscriptions and it's not fun. it is a lot less unfun if you define a month as N calendar days in your terms of service, like virtually everyone does

forty 4y ago
Yes, that's what we do mostly, except to track external subscriptions that actually use months (I believe the Google playstore does that but I could be mistaken with another service)
inopinatus 4y ago
And they would be guilty of misleading the consumer when doing so, and possibly accounting fraud as well because neither GAAP nor IFRS recognise such a calendar; the closest available is the 4-4-5 standard. This is why we don’t let engineers write contracts. Many seem to think that law is a programming language in which they can redefine reality. It ain’t.