Sort an array of objects based on another array of ids

Question

I have 2 arrays

a = [2,3,1,4]
b = [{id: 1}, {id: 2}, {id: 3}, {id: 4}]

How do I get b sorted based on a? My desir

Answer 1

I am going to iterate on arcseldon's solution.

The right approach here is to flip the problem, instead of "sorting a based on the order given by b", I'd rather "enrich b with data coming from a"

This lets you maintain the time complexity of this function down to O(n), instead of bringing it up to O(n2).

const pickById = R.pipe(
  R.indexBy(R.prop('id')),
  R.flip(R.prop),
);

const enrich = R.useWith(R.map, [pickById, R.identity]);


// =====

const data = [2, 3, 1, 4];
const source = [{ id: 1 }, { id: 2 }, { id: 3 }, { id: 4 }];

console.log(
  enrich(source, data),
);