[NgClass] how to manege priority.

[topaz urchin]

Hello friends i have a div with ngClass:

<div [ngClass]="myValue.length > 0 ? 'myClass1' : 'myClass2' ">
</div>

And its work fine, but in some point of my code, the variable "myValue" become null or empty, and in that point my application goes down because cant read length of undefined.

So... how can i make the "if" inside the ngClass to verify first if myValue isnt null, undefined or empty, before check if the length is > 0

[jagged herald]

IMPO, you shouldn't do logic in your template. But if you must

<div [ngClass]="(myValue?.length ?? 0) > 0 ? 'myClass1' : 'myClass2' ">
</div>

[topaz urchin]

hi Rob! glad to see you!

what the ?? 0 means?

(?? 0)

[jagged herald]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_operator

It means "if myvalue?. is null-ish, then use the right hand side of ??, or zero in this case

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining

[topaz urchin]

Wooow, i search a lot on google and nobody told me that, thanks RoB!!!

Its workiiiingggg Rooooooooooooooooob

i gonna finish it before the deadline!