Tiny immutable set implementation

example.js

const o1 = {k1: {k2: false}};

const o2 = setImmutable(o1, ["k1", "k2"], true);

console.log(o1 === o2); // false
console.log(o1.k1 === o2.k1); // false
console.log(o1.k1.k2 === o2.k1.k2); // false

set-immutable.js

const shallowClone = objectOrArray => (
  Array.isArray(objectOrArray) ?
    Array.from(objectOrArray) :
    Object.assign({}, objectOrArray)
);

const setAndReturn = (object, key, value) => {
  object[key] = value;

  return value;
};

const ensureImmutable = (root, path) => path
  .slice(0, -1)
  .reduce((current, segment, index) => setAndReturn(
    current,
    segment,
    segment in current ?
      shallowClone(current[segment]) :
      getSegmentValue(path[index + 1])
  ), root);

const setWith = (ensure, root, path, value) => {
  const destination = ensure(root, path);

  const key = path[path.length - 1];

  destination[key] = value;

  return root;
};

const setImmutable = (root, path, value) => setWith(
  ensureImmutable,
  shallowClone(root),
  path,
  value
);

export default setImmutable;