@thi.ng/associative/intersection.js

ES Map/Set-compatible implementations with customizable equality semantics & supporting operations

import { empty } from "@thi.ng/object-utils/empty";
import { __combineSet } from "./internal/combine.js";
import { into } from "./into.js";
const intersection = (a, b, out) => {
  out = out || empty(a, Set);
  if (a === b) {
    return into(out, a);
  }
  if (b.size < a.size) {
    return intersection(b, a, out);
  }
  for (const i of b) {
    if (a.has(i)) {
      out.add(i);
    }
  }
  return out;
};
function intersectionR(src) {
  return __combineSet(intersectionR, intersection, src);
}
export {
  intersection,
  intersectionR
};