bbo/intersect_by.js

bbo is a utility library of zero dependencies for javascript.

'use strict';

/**
 * Returns a list of elements that exist in both arrays,
 * after applying the provided function to each array element of both.
 */
function intersectBy(a, b, fn) {
  var s = new Set(b.map(fn));
  return a.filter(x => s.has(fn(x)));
}

module.exports = intersectBy;