docCount.js

const query = { 
    food_drink      : { match: { topics: 'food_drink' } },
    fashion         : { match: { topics: 'fashion' } },
    real_estate     : { match: { topics: 'real_estate' } },
    vehicle         : { match: { topics: 'vehicle' } },
    job             : { match: { topics: 'job' } },
    learn           : { match: { topics: 'learn' } },
    emtertainment   : { match: { topics: 'emtertainment' } }
};

const filter = { range: { air: { gte: 1517778314240 } } };

esClient.search({
    index: 'posts', // elasticsearch index
    type: 'post', // elasticsearch type
    body: {
        "size"  : 12, // return no detail about found posts
        "query" : query, // plugin your query
        "aggs"  : { "messages" : { "filters" : { "filters" : filters }} }, // plugin your filter
        _source: ['title','url','photos','viewed'], //  controlled returned fields
    }
}).then(resp => { cb(null, resp)}).catch(err => cb(err, null));

//{ 
//    took: 15,
//    timed_out: false,
//    _shards: { total: 5, successful: 5, skipped: 0, failed: 0 },
//    hits: { total: 12345678, max_score: null, hits: [ [length]: 0 ] },
//    aggregations: { 
//        messages: { 
//            buckets: { 
//                food_drink      : { doc_count: 433 },
//                fashion         : { doc_count: 346 },
//                real_estate     : { doc_count: 2342 },
//                vehicle         : { doc_count: 424 },
//                job             : { doc_count: 4567 },
//                learn           : { doc_count: 8763 },
//                emtertainment   : { doc_count: 4542 },
//            }
//        }
//    }
//}