CODEWITHSUNDEEP
actionscript-3
A-OK
A-OK

Reputation: 3254

AS3 - how to check if a variable exists?

if (XMLData.product[i].image[0].thumb) {thumbURL = XMLData.product[i].image[0].thumb;}

Returns: TypeError: Error #1010: A term is undefined and has no properties.

Same with

if (XMLData.product[i].image[0].thumb!=undefined) {thumbURL = XMLData.product[i].image[0].thumb;}

How do I check if a variable exists?

Upvotes: 0

Views: 2270

Answers (2)

user562566
user562566

Reputation:

PFhayes is right, you need to ensure each level of properties you're stepping through are defined. OR, if you want to be lazy, you can just write it in a try/catch statement. Like so:

if (XMLData.product[i] && XMLData.product[i].image[0] && XMLData.product[i].image[0].thumb)
{
    thumbURL = XMLData.product[i].image[0].thumb;
}else{
   //Not defined somewhere
}

or

try{
     thumbURL = XMLData.product[i].image[0].thumb;
}catch(err:Error){
     //Something went wrong. You can analyze the error data from here and act accordingly
}

Upvotes: 1

pfhayes
pfhayes

Reputation: 3927

The correct way is to compare it to undefined (though you should use !== instead of !=). It may be possible that it is an earlier object is undefined. To help debug this problem, you may need to check that

XMLData
XMLData.product
XMLData.product[i]
XMLData.product[i].image
XMLData.product[i].image[0]
XMLData.product[i].image[0].thumb

are all not equal to undefined.

Upvotes: 5

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