Automation

Hi All

Should be a silly question, but anyway. I'm trying to understand the need of

using jcs:empty() function. What is the difference between the following code blocks

if ($a) { ... }

if (not(jcs:empty($a)) ) { ... }

It looks like $a will be converted to false anyway (if it is empty).

So is there a case when jcs:empty is really needed?

Well, you could summarize this as follows:

if( $a == true() )

versus:

if( not( jcs:empty( $a ) ) )

So the first one tests if the argument is true, while the second one checks if the argument is empty. These two checks are identical for strings and node-sets because their boolean test consists of checking if they are empty or not; however, these two tests are not equivalent for numbers or booleans since those two data types can never be empty but they can be false.

For example:

var $a = 0;

if( $a )

Is not the same as:

if( not( jcs:empty( $a ) ) )

Because a number is never empty, but a number with a value of 0 is considered to be false.

As far as why jcs:empty() is needed, you're correct that you can achieve the same result using other means, but the advantage of jcs:empty() is it makes it very clear what you are testing for, whereas node-set boolean tests might not be as obvious to script writers with less experience.

Hi Curtis,

Very good explanation, thank you very much!