import { groupBy } from "../../src/collections/groupBy";

describe("groupBy()", () => {
  it("groups items by provided key function", () => {
    const data = [{ id: 1 }, { id: 2 }, { id: 1 }];
    const grouped = groupBy(data, (x) => x.id);
    expect(grouped).toEqual({ "1": [{ id: 1 }, { id: 1 }], "2": [{ id: 2 }] });
  });
});