Apply an object of functions to 2 others of Data to arrive at a new one where each key has had its special function run against the other's values.

mergeWithStrategy.js

const selectBrevity= (l, r) => lte(length(l), length(r))
  ? l
  : r;

const lispy = ([fn, ...args]) => fn(...args);

const makeSet = (arr) => uniq(flatten(arr));

const zipObjLisped = (arr) => ({ [head(arr)]: lispy(tail(arr)) });

const medianArgs = (...args) => median([...args])

const sumArgs = (...args) => sum([...args])

const mergeWithStrategy = (rubrick, a, b) => compose(
  reduce(
    (acc, item) => merge(acc, zipObjLisped(makeSet(item))),
    {}
  ),
  zip(toPairs(rubrick)),
  zip(toPairs(a))
)(toPairs(b));

const dataA = {
  baths: 2,
  beds: 1,
  type: 'residential',
  year: 2011,
};

const dataB = {
  baths: 4,
  beds: 5,
  type: 'single family residential',
  year: 2008,
};

const elegantePrimo = {
  baths: medianArgs,
  beds: max,
  type: selectBrevity,
  year: sumArgs,
};

mergeWithStrategy(
  elegantePrimo,
  dataA,
  dataB
);