🚀 go-pugleaf

well, after some more digging into it, I found the bugs and corrected, here is the corrected version (now I only need to figure out how to do it on an entire book...):

if (app.documents.length > 0) {
	var myDocument = app.activeDocument;
	var myHyperlinkStyle = myDocument.characterStyles.item("hyperlink"); // replace hyperlink with name of your char style for links
	//alert(myHyperlinkStyle);
	main();
} else {
	alert("Please open a document");
}

function main() {
	app.findGrepPreferences = NothingEnum.nothing;
	app.changeGrepPreferences = NothingEnum.nothing;

	//the value to find
	myFindVal = "page (\\d+)";
	doSearchAndReplace(myFindVal, app.activeDocument);
	// reset search
	app.findGrepPreferences = NothingEnum.nothing;
	app.changeGrepPreferences = NothingEnum.nothing;
}

function doSearchAndReplace(stringfind, searchin) {
	app.findGrepPreferences.findWhat = stringfind;

	//Set the find options.
	app.findChangeGrepOptions.includeFootnotes = true;
	app.findChangeGrepOptions.includeHiddenLayers = false;
	app.findChangeGrepOptions.includeLockedLayersForFind = false;
	app.findChangeGrepOptions.includeLockedStoriesForFind = false;
	app.findChangeGrepOptions.includeMasterPages = false;

	var myFoundItems = searchin.findGrep();

	for (i = 0; i < myFoundItems.length; i++) { 		var item = myFoundItems[i].contents; 		//the destination page 		var destPageNumber = item.slice(5);

		var destPage = searchin.pages.itemByName(destPageNumber);
		var myHyperlinkDestination = myMakeHyperlinkDestination(destPage);
		myMakeHyperlink(myFoundItems[i], myHyperlinkDestination);
		myFoundItems[i].applyCharacterStyle(myHyperlinkStyle, false);
	}
}

function myMakeHyperlink(myFoundItem, myHyperlinkDestination){
	try {
		var myHyperlinkTextSource = myDocument.hyperlinkTextSources.add(myFoundItem);
		var myHyperlink = myDocument.hyperlinks.add(myHyperlinkTextSource, myHyperlinkDestination);
		myHyperlink.visible = false;
	}
	catch(myError){
	}
}

function myMakeHyperlinkDestination(myDestPage){
	//If the hyperlink destination already exists, use it;
	//if it doesn't, then create it.
	try{
		var myHyperlinkDestination = myDocument.hyperlinkDestinations.item(myDestPage);
		myHyperlinkDestination.name;
	}
	catch(myError){
		myHyperlinkDestination = myDocument.hyperlinkPageDestinations.add(myDestPage);
		myHyperlinkDestination.destinationPage = myDestPage;
	}
	//myHyperlinkDestination.name = myDestPage.name;

	//Set other hyperlink properties here, if necessary.
	return myHyperlinkDestination;
}