Renumber Footnotes in InDesign Book

#target indesign

var doc;
var footnoteCount=1;
if((app.books.length==1) && (app.documents.length==0)) {
    var bookFiles=app.books[0].bookContents.everyItem().fullName;
    if(bookFiles.length>1) {
        doc=app.open(bookFiles[0], false, OpenOptions.OPEN_ORIGINAL);
        setFootnoteOptions();
        for(var i=1; i<bookFiles.length; i++) {
            footnoteCount+=doc.stories.everyItem().footnotes.everyItem().id.length;
            doc.close(SaveOptions.YES);
            doc=app.open(bookFiles[i], false, OpenOptions.OPEN_ORIGINAL);
            setFootnoteOptions();
            }
        doc.close(SaveOptions.YES);
        }
    }

function setFootnoteOptions() {
    doc.footnoteOptions.restartNumbering=FootnoteRestarting.DONT_RESTART;
    doc.footnoteOptions.startAt=footnoteCount;
    }