Array intersection based on function

OSCC · JavaScript, Array · Oct 20, 2020

Returns the elements that exist in both arrays, using a provided comparator function.

  • Use Array.prototype.filter() and Array.prototype.findIndex() in combination with the provided comparator to determine intersecting values.
const intersectionWith = (a, b, comp) =>
  a.filter(x => b.findIndex(y => comp(x, y)) !== -1);
intersectionWith(
  [1, 1.2, 1.5, 3, 0],
  [1.9, 3, 0, 3.9],
  (a, b) => Math.round(a) === Math.round(b)
); // [1.5, 3, 0]

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    Returns every element that exists in any of the two arrays at least once, after applying the provided function to each array element of both.