How can I detect the child element of a variable parent in E4X (Flex 3, specifically)?

Question

I have XML that looks like this:

<question>
    <type_elt>
        <opt_out_flag />
    </type_elt>
</question>

type_elt is not an element name; it might be <single>, <multiple> or something else, determined at runtime. How, given this, can I detect the presence of the opt_out_flag element?

I tried this (where xml refers to the question element):

if (xml.*.opt_out_flag) {
    do_something();
}

but even in cases without opt_out_flag the above expression returns true. Obviously I'm missing something, but what is it?

Answer 1

I believe you want to use xml.*.hasOwnProperty('opt_out_flag') rather than what you're currently using.

Answer 2

Can you be guaranteed that <opt_out_flag/> will always be in the first child of the <question> element? If so, something like the following should work:

(disclaimer: I know this works with attributes, but I don't know if it will work with child elements)

if( "opt_out_flag" in xml.children()[0] ) {
    doSomething();
}

Answer 3

Try this

xml..opt_out_flag

It will search for all occurrence

Answer 4

Hi, can you use the descendants method (which recurses down the tree) to find the tag?

var optOutNodes:XMLList = xml.descendants("opt_out_flag");

if(optOutNodes.length())
{
   //do code here
}

Hope this is what you are looking for.

Answer 5

You can use

var optOut:Boolean = xml..opt_out_flag != undefined

you can omit the != undefined part, but I would leave it there for readability.