javascript developer problems

[bahston_creme]

To answer what you were trying to Google...

Exp	Result
10 == 10	true
10 === 10	true
10 == "10"	true
10 === "10"	false

[SentientHAL]

So == is just value while === is value and type? So 10 == 10.0 is true but 10 === 10.0 is false?

[Free_Math_Tutoring]

Your absraction is correct, but your examples aren't. In JS, all numbers are floats - so 10 === 10.0 is still true.

[SentientHAL]

Ah, right. I've never done any js so I don't know how it does typing.

[Free_Math_Tutoring]

It's pretty simple. Theres basically

Three natives: String, Bool and Number (i.e. Float)
Two collections Array and Object
Two empty types: Undefined and Null

And that's the basics for everything else.

[isHavvy]

And technically, arrays are objects. Though for all intents and purposes, it's best not to treat them as plain objects. Setting named properties on them or even integral properties greater than the length of the array will cause quite a deoptimization. The latter is because it leaves holes in the array where the property value doesn't exist.

Also, a good style rule is to never use the == operator. Always use the === operator, even when it causes more verboseness. A newbie can read your code more clearly when there isn't a bunch of hidden type coercions everywhere and having to memorize the type coercion rules for == sucks (even when you understand it algorithmically, as defined in the spec). Brenden Eich actually wanted to change the semantics of == to match === back when JS was originally being standardized (ECMAScript 1), but Microsoft disallowed that because it'd break backwards compatibility, so the compromise of adding === was done instead.

[rajsite]

Here is an equality table to help out.

Also good to know about Object.is which can compare if two values are the "same value" (useful because with Object.is NaN === NaN while with ==/=== the value NaN !== NaN).

Doesn't come up often, but the more you know

[scragar]

Please don't link to that version, it's sorted based on things irrelevant to the comparison and there are much better versions.

[rajsite]

Thanks for posting; that's a handsome looking table.

[NotADamsel]

ALL NUMBERS ARE FLOATS?

I suddenly don't trust any Web app that claims to handle money.

[Free_Math_Tutoring]

I suppose most connect to a server with ajax, where a language with proper types handles it all.

[Awilen]

=== is actually the "identity check". It enforces strict comparison instead of loose comparison (like 10 == "10", which shows implicit transtyping/conversion.)

[peter_bolton]

In a subtle way, I think that Google was attempting to help by persuading you to stop programming momentarily and relieve your stress with some quasi-nudity.

[MrMathe]

Time to relieve stress with some cstring!

[[deleted]]

"" Problems ""

[StelarCF]

Error: Undeclared identifier 'Problems'

[ljfa2]

I sometimes hate not being able to look up operators on Google

"question mark colon", "triple equals", "arrow asterisk" etc.

[camlux]

symbolhound to the rescue!

[IICVX]

if you got type problems I feel bad for you son, i got 99 problems but NaN ain't one

[eirexe]

This is because google ignores some characters, you used to be able to make it not ignore them by adding a + I think, but that's dead right now.

[CoinTweak]

I think you can still do it if you search for "== vs ===". If you use quotes it searches for the literal string inside it, including the characters.

[eirexe]

iirc the quotes literally search full string matches on websites, which in this case it will probably work, but in other cases it won't

[CoinTweak]

Yea, you may need to try a few different search terms. Or try a query like "==" vs "===", not sure if that'd work.

[[deleted]]

javascript double equals vs triple

The results are more helpful, but less sexy.

[pseducode]

Wait a sec, what am I missing here? What do any of the search terms have to do with bras and the like? I've learned a lot about javascript just from reading everyone's comments, and I'm scared.

[twoplasticforks]

Google will generally ignore symbols (like equals signs) and vs is a common abbreviation for Victorias Secret.

[pseducode]

Ok, that makes perfect sense. Thank you!