Javascript Date method inconsistency - getDate vs getMonth

Question

This caused me a bit of a headache last night and I wanted to understand why the getDate method in the Date object is 1 based (returns values from 1-31) while the getMonth m

Answer 1

I suppose months are 0-based because Java did it the same way when the JavaScript language was designed.

EDIT Oracle took down older Java documentation, there is an archived version of that page.

Answer 2

In JavaScript, counters start at zero.

Months do not necessarily have to be represented by a digit. "Months" is a countable sequence. The first element of this sequence is referred by zero.

In real-life, days are represented by a fixed digit. Although days are also countable, it would be extremely confusing to represent the first day as Day Zero.

Answer 3

So I dropped Brendan Eich a tweet asking him the question (for those who don't know he is the creator of JS) and his response was:

@magrangs because that is how java.util.Date did it.

https://twitter.com/BrendanEich/status/179610205317902337

Answer 4

Hard to tell, but I have a suspicion that Month is 0-based so it can be easily used as an indexer in a months array that holds month names

var months = new ["Jan", "Feb", ....]
months[new Date().getMonth()];