Replace document fonts in InDesign CS6, js

Question

Hi,
I need to replace document fonts in InDesign. I get the existing fonts with following script, but not sure how to replace let's say Helvetica Regular with Aria Regular:
for(var counter = 0; counter < document.fonts.length; counter++){
            //If the <fontFamily> element for this font family does not already exist in the XML, add it.
            if(counter > 0){
fontFamilyName = document.fonts.item(counter).fontFamily;
                    fontFamilyName.toString().replace(/\s*\(TT\)$/gi, "");
                    alert (fontFamilyName);
                    fontName = document.fonts.item(counter).name;
            alert (fontName);
            fontName = fontName.split("\t");
            fontStyle = fontName[1];
            if(fontStyle == "BoldBold"){
                fontStyle = "Bold";
            fontName = fontName[0];
            alert (fontName);
Thank you.
Yulia

Answer 1

Yuliart please mark as correct
Virender,
I didn't put in the font style because it wasn't asked for but if you are finding both the font and the style as in your example then you don't need to do a separate line for the style
Just use
app.findTextPreferences.appliedFont = "Arial\tRegular";
I.e. the font name seperate from its style by a tab \t
You only need to use a separate line fontStyle if you are looking for that style irrespective of which font the style is applied to although some might argue to use it for readability.
Regards
Trevor