A sample query object that uses functions to filter a collection

query.js

class Query {

  constructor(coll) {
    this.coll = coll;
  }

  getCollection() {
    return this.coll;
  }

  find(id) {
    return new Query(_.each(this.coll, item => item.id === id));
  }

  select(predicate) {
    return new Query(_.filter(this.coll, predicate));
  }

  groupBy(fn) {
    return new Query(_.groupBy(this.coll, fn));
  }

  sortBy(valueFn) {
    return new Query(_.sortBy(this.coll, valueFn));
  }

}

let query = new Query(this.FileCache.getAll());
let results = query
  .select((item) => item.title.matches(/regexhere/) && item.headline.empty())
  .sortBy((item) => item.createDate)
  .getCollection();