[flexcoders]How would you rewrite this isset PHP condition in AS3?

[dorkie dork from dorktown]

I have a PHP statement that I am trying to write in AS3. So far it errors
out because the properties do not exist on it yet. How would/should I
rewrite this for AS3? Here is the statement:

// at the time this is run "this.language_data" is an object with 2
properties
// the "STYLES" property does not exist yet and it generates a
// TypeError: Error #1010: A term is undefined and has no properties.
if (isset(this.language_data['STYLES']['BRACKETS'][0])) {

ddfd