sortByProps.js

import { comparator, curry, either, lt, map, prop, reduce, sort } from 'ramda';

/**
 * Sort a list of objects by a list of props (if first prop value is equivalent, sort by second, etc).
 *
 * @func sortByProps
 * @memberOf RA
 * @since {@link https://char0n.github.io/ramda-adjunct/2.26.0|v2.26.0}
 * @category List
 * @sig [k] -> [{k: v}] -> [{k: v}]
 * @param {Array.<string>} props A list of properties in the list param to sort by
 * @param {Array.<object>} list A list of objects to be sorted
 * @return {Array.<object>} A new list sorted by the properties in the props param
 * @example
 *
 * sortByProps(['num'], [{num: 3}, {num: 2}, {num: 1}])
 * //=> [{num: 1}, {num: 2} {num: 3}]
 * sortByProps(['letter', 'num'], [{num: 3, letter: 'a'}, {num: 2, letter: 'a'} {num: 1, letter: 'z'}])
 * //=> [ {num: 2, letter: 'a'}, {num: 3, letter: 'a'}, {num: 1, letter: 'z'}]
 * sortByProps(['name', 'num'], [{num: 3}, {num: 2}, {num: 1}])
 * //=> [{num: 1}, {num: 2}, {num: 3}]
 */

const sortByProps = curry((props, list) => {
  const firstTruthy = ([head, ...tail]) => reduce(either, head, tail);
  const makeComparator = (propName) =>
    comparator((a, b) => lt(prop(propName, a), prop(propName, b)));
  return sort(firstTruthy(map(makeComparator, props)), list);
});

export default sortByProps;