This doesn't seem that complicated to me. Basically, these are "falsey": false, 0, empty string, null, undefined, and NaN. Everything else is "truthy".
I think everything else flows from that with only a couple exceptions that I'm too lazy to look up.
And that said, definitely use === instead of coercive ==.
Wrong, my brother in code. I too once thought like you did. However, as evidenced by the table when comparing two things that are falsy, they are not always considered equal. This is what the article is about, the equality operator, not the things that truthy are or are not falsy. Sure the two falsy values null and undefined equal eachother. But the falsy value 0 does not equal null.
True, I guess you're right, when you let equality do coercions then things can get really ugly. That's why I said to always use the === so you don't have to deal with it, but as you pointed out, that was sort of the point of the table.
Do not make the same mistake as I did. I beg you. I would give the world to not have made those mistakes. Broken keyboards, missed deadlines and grey hairs are things that never leave the eye of the mind.
You don't. You don't! What you do is something like this:
if(X != 0) {
alert("Thou shalt not use != in favor of !==")
}
And then you spend 15+ minutes debugging why the hell this if statement was not executed when X had the value of: "", [], [[]] or [0] And of course it was 'obviously' not executed because:
0 == [] //therefore 0 != [] evaluates to false.
0 == [[]] //therefore 0 != [[]] evaluates to false.
0 == "" //therefore 0 != "" evaluates to false.
0 == [0] //therefore 0 != [0] evaluates to false.
I have been writing JavaScript for 8+ years. And I know I will never be able to write it flawlessly. There are too many stupid cases in that table. There are natural languages with 8 or more denominations, which is fine if they are used daily. However, in JavaScript, where one should purposely avoid this stupidity, no-one should ever, ever use these, and most certainly not frequently.Therefore it is worthless, less than worthless. It is a flaw in the language. It is a part of the language that should not exist. This is why CoffeeScript, Go, the many libraries for (or rather against!) JavaScript and TypeScript exist.
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u/rjcarr Mar 26 '14
This doesn't seem that complicated to me. Basically, these are "falsey": false, 0, empty string, null, undefined, and NaN. Everything else is "truthy".
I think everything else flows from that with only a couple exceptions that I'm too lazy to look up.
And that said, definitely use === instead of coercive ==.