mongodb export indexes with expiration

mongo-coll-indexes.js

var always_background = true;
db.getCollectionNames().forEach(function(collection) {
   indexes = db.getCollection(collection).getIndexes();
   if(indexes && indexes.length>0) {
        print("//Indexes for " + collection + ":");
        indexes.forEach(function(index) {
       var options = {};
       if(index.unique) {
           options.unique = index.unique;
       }
       if(index.sparse) {
           options.sparse = index.sparse;
       }
       if(index.background) {
           options.background = index.background;
       }
       if(index.expireAfterSeconds) {
           options.expireAfterSeconds = index.expireAfterSeconds;
       }
       if(always_background) {
           options.background = true;
       }
       options = JSON.stringify(options);
       var key = JSON.stringify(index.key);
       if(key !== '{"_id":1}') {
        print('db.getCollection("' + collection + '").createIndex(' + key + ', ' + options + ');');
       }
    });
   }
});