getFilteredPersons.js

// takes a contract and returns an array of all the persons that passed the filters
// add as many filters as you want to the list, e.g.: filterBySalary, etc
// sort your filters so the most expensive ones are closer to the end, working with the less data
const getFilteredPersons: (Contract, ... => Array<Person>) = _.flow([
    _.get('personnel'),
    filterByPosition(positionFilter),
    filterByDate(startDate, endDate),
    filterByStatus(statusFilter, timeRange),
    _.sortBy(sortKey),
    R.when(
       () => sortDirection === 'ascending', // when this predicate is true..
        _.reverse, // reverse the persons array, otherwise return array untouched
    ),
]);

// 'flow' is just a reverse 'compose', _ is lodash, R is ramda
// all filterByXXX functions are curried and have a signature of Array<Person> => Array<Person>