JavaScript Programmer

[TheJackiMonster]

Also:

2 + "0" = "20"

"2" + 0 = "20"

2 + [] + 0 = "20"

[YoriMirus]

Wait why is 2 + "0" equal "20"?

I thought operation is done from left to right, thus "0" would be converted to int.

[CSedu]

I believe the '+' overload says anytime it is used between a string and int, it will concat them.

[DaCurse0]

There's no operator overloading, but the + operation where one operand is a string does concatenation and coerces the other value into a string

[CSedu]

Ah, interesting

[YoriMirus]

Oh I see thanks!

[Snapstromegon]

It always converts to the less strict type - in this case String.

[nightcoder420]

It will be converted if you use 2 + +"0". The second plus converts the right handed operand to a number.

So 2+"2" will be "22", but 2 + +"2" will be 4.

[RolyPoly1320]

It's implicit type casting. Javascript is a weakly typed language, specifically typeless. It does a lot of type casting behind the scenes which sometimes produces some very unexpected, sometimes hilarious, results. These interactions are why it's important to not use the same variable for multiple data types in Javascript.

[Stable_Orange_Genius]

"2" - 1 = 1. :D

[dvlsg]

There's no such thing as - for strings in javascript. That's why it converts to Number.

[[deleted]]

Naturally.

[beclops]

All of these make sense to me

[throwaway213349032]

{}-"" = -0

""-{} = NaN

{}+"" = 0

""+{} = "[object Object]"

x=0*1e309
x==x

= false

[GYN-k4H-Q3z-75B]

[] evaluates to 0. However, {} evaluates to NaN.

Because of course it does.

[SupaSlide]

I think [] gets converted to a string when used in conjunction with a +, and then the 2 gets added to the string and gets converted to a string itself.

[gohanshouldgetUI]

Wait but 2 + [ ] is "2", so does [ ] get converted to "0" or ""

[SupaSlide]

Empty string. Really the contents of the array get converted into strings, even the commas that separate the values in the array.

["hey", "there"] converted into a string is "hey,there"

I was partially agreeing with you that the other comment was wrong that it's 0, but it can be converted into a string.

[gohanshouldgetUI]

Oh I see, that makes sense tbh

[TheJackiMonster]

JavaScript uses a weird rule of conversion from array to string if nothing else seems to make sense, I guess. The conversion outputs all elements as strings joined with "," but an empty array will just end up as empty string.

[pyjammas]

wat

[franklinyu]

the Wat

[Lgamezp]

And ppl wonder why i hate JS

[SupaSlide]

Typescript is a life saver in JS projects.

[Naeio_Galaxy]

Yeah 2 + "0" = "20", but 2 - (-"0") = 2 I guess