Mirth String Handling - mirth

Question

I'm using the code below to try and strip the file extension off the incoming file and replace it with "ACK";
Can't use .lastIndexOf as it's not available in Rhino.
var _filename = String(sourceMap.get('originalFilename'));
pos = -1;
var search = ".";
for(var i = 0; i < _filename.length - search.length; i++) {
if (_filename.substr(i, search.length) == search) {
pos = i;
}
}
logger.info('_pos:' + _pos);
Every time I get a pos value of -1
i.e. Last full stop position not found.
BUT if I hardcode the filename in as "2020049.259317052.HC.P.F3M147-G" it works perfectly.
Is it something to do with the sourceMap.get('originalFilename') supplying a non-string or different
character set ?

Answer 1

This was tested on mirth 3.5. Rhino does, in fact, have String.prototype.lastIndexOf for all mirth versions going back to at least mirth 3.0. You were correctly converting the java string from the sourceMap to a javascript string, however, it is not necessary in this case.
Java strings share String.prototype methods as long as there is not a conflict in method name. Java strings themselves have a lastIndexOf method, so that is the one being called in my answer. The java string is able to then borrow the slice method from javascript seamlessly. The javascript method returns a javascript string.
If for some reason the filename starts with a . and doesn't contain any others, this won't leave you with a blank filename.
var filename = $('originalFilename');
var index = filename.lastIndexOf('.');
if (index > 0) filename = filename.slice(0, index);
logger.info('filename: ' + filename);
That being said, I'm not sure why your original code wasn't working. When I replaced the first line with
var originalFilename = new java.lang.String('2020049.259317052.HC.P.F3M147-G');
var _filename = String(originalFilename);
It gave me the correct pos value of 22.

Answer 2

New Answer
After reviewing and testing what agermano said he is correct.
In your sample code you are setting pos = i but logging _pos
New answer var newFilename = _filename.slice(0, _filename.lastIndexOf('.'))
Older Answer
First, you are mixing JavaScript types and Java types.
var _filename = String(sourceMap.get('originalFilename'));
Instead, do
var _filename = '' + sourceMap.get('originalFilename');
This will cause a type conversion from Java String to JS string.
Secondly, there is an easier way to do what you are trying to do.
var _filenameArr = ('' + sourceMap.get('originalFilename')).split('.');
_filenameArr.pop() // throw away last item
var _filename = _filenameArr.join('.') // rejoin the array with out the last item
logger.info('_filename:' + _filename)