You can use put/get custom options to save preference parameters that persist across Photoshop launches:
const kMyFlag = app.stringIDToTypeID( "myFlag" );
const kMyNumber = app.stringIDToTypeID( "myNumber" );
const kMySettings = "mySettings";
function saveSettings()
{
var desc = new ActionDescriptor();
desc.putBoolean(kMyFlag, true);
desc.putInteger(kMyNumber, 42);
// "true" means setting persists across Photoshop launches.
app.putCustomOptions( kMySettings, desc, true );
}
function getSettings()
{
var desc = app.getCustomOptions( kMySettings );
return [desc.getBoolean( kMyFlag ), desc.getInteger( kMyNumber )];
}