Check if child variable value is set

Question

I have a long chain of objects and want to check if the last object in the chain is null. Like this:

if(obj1.obj2.obj3.obj4) {
    // obj4 is not null --> do stuff
}

However if obj3 is null, I get an exception. So I would have to do:

if(obj1.obj2.obj3) {
    // obj3 is not null
    if(obj1.obj2.obj3.obj4) {
        // obj4 is not null --> do stuff
    }
}

obj1 and obj2 might be also null, so I have to check these as well. I'm sure there must be a better way to implement this, instead of doing if-chains.

You don't have to do an if chain, you could add multiple conditions in the first if — Axnyff, Feb 26 '18 at 16:41
He means `if (obj1 && obj1.obj2 && obj1.obj2.obj3 && obj1.obj2.obj3.obj4)` but that's ugly as sin. I'd rather see multiple if statements — Reinstate Monica Cellio, Feb 26 '18 at 16:42
As curiosity, some days ago I discovered a new operator in c# 6 that makes exactly this: obj1?.obj2?.obj3?.obj4?. I haven't found it on javascript yet, but to reduce the pyramid use @Archer comment. — Marc, Feb 26 '18 at 16:48
@Marc Sadly not available in JS yet, but I use it regularly in C#. The 2 languages get closer every update! :D — Reinstate Monica Cellio, Feb 26 '18 at 16:49

score 0 · Answer 1 · answered Feb 26 '18 at 16:42

0

You can check them with && operator

if(obj1 && obj1.obj2 && obj1.obj2.obj3 && obj1.obj2.obj3.obj4) {

}

answered Feb 26 '18 at 16:42

Suren Srapyan

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Check if child variable value is set

1 Answers1