frankiehayward
12/5/2019 - 10:58 PM

intersectionBy

This snippet can be used to return a list of elements that exist in both arrays, after a particular function has been executed to each element of both arrays.

intersection_by.js
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const intersectionBy = (a, b, fn) => {
  const s = new Set(b.map(fn));
  return a.filter(x => s.has(fn(x)));
};

intersectionBy([2.1, 1.2], [2.3, 3.4], Math.floor); // [2.1]