filter-documents.ts

import * as Mingo from 'mingo';

/**
 * FilterOptions
 * FilterOptions can be used to customized how documents are filtered.
 * All fields are optional and they are always used in this order:
 *  1. sort
 *  2. skip
 *  3. limit
 */
export type FilterOptions = {
  sort?: any;
  limit?: number;
  skip?: number;
};

/**
 * createFilterFunction
 * createFilterFunction creates a function which can be used to filter
 * an array of documents. Converts mongodb like query objects to functions.
 *
 * @param filter: A mongodb like filter object.
 */
export const createFilterFunction = (filter: any): Function => {
  const query = new Mingo.Query(filter);
  return (doc: any) => query.test(doc);
};

/**
 * filterDocuments
 * filterDocuments returns a subset of documents using given filter options.
 * The filter parameter is similar to the one used in Mongo database queries.
 */
export const filterDocuments = (filter: any, docs: any[], options: FilterOptions = {}): any[] => {
  let cursor = Mingo.find(docs, filter);
  if (options.sort) {
    cursor = cursor.sort(options.sort);
  }
  if (options.skip) {
    cursor = cursor.skip(options.skip);
  }
  if (options.limit) {
    cursor = cursor.limit(options.limit);
  }
  return cursor.all();
};