if ((x = SomeObj.MethodThatReturnsALong(42)) != null) 1

[JustinEzequiel]

Greetings,

I know some JavaScript but this has me stumped.
I am translating some vendor-supplied code to another programming language and I do not know how an assignment statement can or cannot return a null.
I.e., is the snippet below checking if x is not null?
If not, then what is the condition checking?

var x;
if ((x = SomeObj.MethodThatReturnsALong(42)) != null)
    {
    // more code here
    }

Thanks

 

[BillyRayPreachersSon]

It's an assignment and a check in one go. It could be written as:

var x = SomeObj.MethodThatReturnsALong(42);
if (x != null) {
	// more code here
}

Hope this helps,
Dan



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[JustinEzequiel]

Thanks Dan.
Had scanned w3schools' JavaScript references for this and did not find any mention that one could do this.
I was concerned that my "translation" may not accurately reflect the original.
Thanks again.

 

[feherke]

Hi

I know some JavaScript but this has me stumped.

Just as a note, that is not JavaScript specific. That works in most of the languages with C-like syntax. It is just matter of operator precedence. I do not think you will find that explicitly mentioned in any language reference.

Feherke.

http://rootshell.be/~feherke/

 

[JustinEzequiel]

Just as a note, that is not JavaScript specific. That works in most of the languages with C-like syntax. It is just matter of operator precedence.

Thanks. I will try to remember that.