Logical operators && TRICKS with short-circuit evaluation - Beau teaches JavaScript

Short-circuit evaluation happens when using conditionals with && or ||. The second argument is only evaluated when the first argument is not enough to determine the value of the expression. Learn some tricks using short-circuit evaluation in JavaScript.
Code:
🔗 codepen.io/beau...
More info:
🔗 www.jstips.co/e...
Beau Carnes on Twitter: / carnesbeau
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[@vitaliypogoretsky3199]

|| stops on "truth", && stops on "lie". Remember :)

[@firasalsghier3944]

Thank you you really helped me

[@nahidestes]

well said👏

[@poonamthorup2458]

Comment saved in my notes

[@CambiaAhora]

awesome

[@cheribrandt8918]

feras alsghier Yea

[@bruhmoment3731]

Thank you!

[@shaikhzoyeb]

thanks that's helpful

[@muthimuthi5087]

S qx!x fastest-growing yyxyyyyy try 6dyes ytx city 6dyes d try zzz dyxyxyyxyyxy Urdu and dydydy strategy dyes Rudy x US ydy sags y u uddx 6dye, xyxyxyxxy66xd x dxxdd b h ddxuxuddx hybrid fu d 7dzd h 877xu87xu7877xu87xu7yxyxmmmmmmmmmmm0?+ mhmm mmyxyx TRY RUDY

[@MarcoAntonio-fh7rd]

I was searching for the last explanation, thanks Beau, great tutorial

[@busyrand]

React sent me....

[@aybak3k]

cam here to learn it figured out i do it all the time in bash 😆

[@momakplayz7985]

What about "!" statement?

[@stomperhk9107]

It reverses the value. E.g: !true // false !false // true !0 // true

[@SogMosee]

Is it possible to use short-circuit evaluation with multiple variables? I would think so, but for some reason, this fails: let amountLength = transactionAmountField.value.length === 0, methodLength = methodSelect.value.length === 0, categoryLength = categorySelect.value.length === 0, disable = () => transactionSubmitButton.disabled = true, activate = () => transactionSubmitButton.disabled = false (amountLength || methodLength) && disable() The disable function is not called despite both amountLength and methodLength being equal to 0.

[@SogMosee]

Nevermind, I figured it out! Here is the correct code: !!(amountLength || methodLength) && disable() !!(!amountLength && !methodLength) && activate() The first variable merely needed to be converted into a boolean.

[@andrewmiddleton2308]

@@SogMosee What`s the !! for?

[@fwostedfwakes733]

I'm confused at the 3:40 example. Shouldn't !test run isTrue() instead of isFalse() because !test is actually true?

[@heyman3731]

i hope you have found the solutions or it . but for anyone wondering or confused about that part of code :. if (!test) : means that if test is not true . this is the condition we gave to to js . beau changed the value of test to FALSE . Which resulted in javascript checking if the test is not equal to True , which eventually turn out to be right thats why the block code was executed .

[@Moist_yet_Crispy]

Great video! Thanks for this!

[@christianrodier3381]

That was very helpful thanks

[@keifer7813]

4:49 How can you call a function with no arguments when the function declaration has a parameter?

[@shilpas5441]

Apparently the browser assigns the parameter with 'undefined'. So the function call is still valid.

[@eugenenovikov671]

function(name) { name = name } - are u serious?????????????????????

[@elhadiziat764]

very confusing explanation with very quick code writing!

[@CarlosEstebanLopezJaramillo]

You know what's lacking? to explain the caution when using short circuit evaluation when assigning a boolean, what if you expect a boolean but you just want to avoid having null or undefined?

[@stomperhk9107]

Use the double not (!!) operator or the double question mark (??) operator, I didn't undestand wgat you tried to say.

[@CarlosEstebanLopezJaramillo]

@@stomperhk9107 Can't remember what I was going for, probably exactly that (??) operator, which I think did not exist or was not yet implemented 4 years ago when I made the comment.

[@stomperhk9107]

@@CarlosEstebanLopezJaramillo Uhum, I see. I think that it didn't existed 4 years ago either.

[@CarlosEstebanLopezJaramillo]

@@pixelyd7729 Don't have a reason to change it.

[@keifer7813]

@@CarlosEstebanLopezJaramillo I wouldn't remember either after 5 years haha

[@GretSeat]

I'm even more confused now.

[@emilybrock3822]

Yife

[@marianenkoulas4953]

Gbvgg

[@roguehoe]

Uh