Two NSStrings are same but different when you compare them

Recently I was shocked by the fact that two NSStrings that resemble each other on NSLog may be different. It is because sometimes NSString can contain a zero width space character. Be aware of that and consider:

    #define ZERO_WIDTH_SPACE_STRING @"\u200B"

To conquer this you should clean your string from zero width white space characters before comparing:

    NSMutableString *eMailToAdd = [NSMutableString string];
	
    NSMutableCharacterSet *charSet = \
[[NSCharacterSet whitespaceCharacterSet] mutableCopy];
    	//[charSet formUnionWithCharacterSet:\
[NSCharacterSet punctuationCharacterSet]];
    	
        NSString *rawStr = [[tokenField textField] text];
    	for (int i = 0; i < [rawStr length]; i++)
    	{
    		if (![charSet characterIsMember:\
[rawStr characterAtIndex:i]])
    		{
    			[eMailToAdd appendFormat:\
@"%@",[NSString stringWithFormat:@"%c",\
 [rawStr characterAtIndex:i]]];
    		}
    	}