• Nov 11, 2009 | 0 comment(s)
• Posted in: Flash

AS3 version of PHP’s empty() function

When working in PHP I often find the empty() function handy for checking whether a variable is empty or has a zero value. It’s great because I can use it to check different types of variables: boolean, string, array and any variable that is null, or declared but without a value in the class. So I decided to write a similar function in AS3 for my Flash projects. Here it is:

public static function empty(variable:*) : Boolean {

	var isEmpty:Boolean;

	if (variable == null || variable == undefined) {
		isEmpty = true;
	}
	else if (variable is String) {
		var str:String = variable.replace(/^\s+|\s+$/g, '');
		isEmpty = (str.replace(/\s+/g, ' ') == "" || variable == "" || variable == "0" || variable == "false");
	}
	else if (variable is Number || variable is int || variable is uint) {
		isEmpty = (variable == 0);
	}
	else if (variable is Array) {
		isEmpty = (variable.length == 0);
	}
	else if (variable is Boolean) {
		isEmpty = (variable == false);
	}

	return isEmpty;

}

Similar to the PHP version but with some extras, the following things are considered to be empty and will return false:

• NULL
• UNDEFINED
• 0 (0 as a Number, int or uint)
• “” (an empty String)
• ” ” (a String containing only whitespace)
• “0″ (0 as a String)
• “false” (false as a String)
• FALSE (Boolean)
• Array() (an empty array or an array of zero length)
• var myVar:*; (a variable declared, but without a value)

If you have any suggestions or improvements to this, let me know and I’ll update it.

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