Suppress if External Data Field is Empty

[dml1280]

I have an external data field to pull addresses and phone numbers. We don't have fax numbers for every location.

Is there a way to suppress the line if the fax number is blank in the external data field?

Here is the code I am using:

returnStr = '';

if(FusionPro.Composition.isPreview == true || FusionPro.inValidation == true)
{
    Rule("OnJobStart");
}

numRecsExtDF = externalDF.recordCount;

for (recordWalker=1; recordWalker <= numRecsExtDF; recordWalker++)
{
    if (TaggedTextFromRaw(externalDF.GetFieldValue(recordWalker, 'Facility')) == UntaggedDataField("Facility"))
    {
        returnStr += "F:"+externalDF.GetFieldValue(recordWalker, 'Fax Label');
        returnStr += " "+externalDF.GetFieldValue(recordWalker, 'Fax');
    }
}

return returnStr;

"Suppress if Empty" in the text box doesn't work here because there is text (The "F:"). So I need to suppress the "F:" if there is no fax number in the external data field.

 

Thank you.