@thi.ng/associative/indexed.js

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

import { empty } from "@thi.ng/object-utils/empty";
import { selectKeysObj } from "@thi.ng/object-utils/select-keys";
import { EquivMap } from "./equiv-map.js";
const indexed = (records, ks) => {
  const res = new EquivMap();
  let x, ik, rv;
  for (x of records) {
    ik = selectKeysObj(x, ks);
    rv = res.get(ik);
    !rv && res.set(ik, rv = empty(records, Set));
    rv.add(x);
  }
  return res;
};
export {
  indexed
};