sflow/src/flats.spec.ts

sflow is a powerful and highly-extensible library designed for processing and manipulating streams of data effortlessly. Inspired by the functional programming paradigm, it provides a rich set of utilities for transforming streams, including chunking, fil

import { sf } from ".";
import { sflow } from "./sflow";

it("works", async () => {
  let i = 0;
  const rs = new ReadableStream<number[]>(
    {
      pull: (ctrl) => {
        console.log("pull st " + i);
        ctrl.enqueue([i, i + 1]);
        ++i < 2 || ctrl.close();
      },
    },
    { highWaterMark: 0 },
  );
  expect(await sflow(rs).flat().log().toArray()).toEqual([0, 1, 1, 2]);
});
it("works", async () => {
  let i = 0;
  const rs = new ReadableStream<number[]>(
    {
      pull: (ctrl) => {
        console.log("pull st " + i);
        ctrl.enqueue([i, i + 1]);
        ++i < 2 || ctrl.close();
      },
    },
    { highWaterMark: 0 }
  );
  expect(await sflow(rs).flat().log().toArray()).toEqual([0, 1, 1, 2]);
});

it("works with [] with filter", async () => {
  await sflow([[1, 2], [3, 4], [], [5, 6]])
    .filter((e) => e.length)
    .flat()
    .log()
    .toArray()
    .then((a) => expect(a).toEqual([1, 2, 3, 4, 5, 6]));
});

it("works with [] without filter", async () => {
  await sflow([[1, 2], [3, 4], [], [5, 6]])
    .by(sf.flats())
    .log()
    .toArray()
    .then((a) => expect(a).toEqual([1, 2, 3, 4, 5, 6]));

  await sflow([[1, 2], [3, 4], [], [5, 6]])
    .flat()
    .log()
    .toArray()
    .then((a) => expect(a).toEqual([1, 2, 3, 4, 5, 6]));
});

// const lazyStream = (fn: AnyFunction, i = 0) =>
//   new ReadableStream<number[]>(
//     {
//       pull: (ctrl) => {
//         fn();
//         const dat = [i, i + 1];
//         ctrl.enqueue(dat);
//         console.log("pull st " + dat);
//         ++i < 5 || ctrl.close();
//       },
//     },
//     { highWaterMark: 0 }
//   );

// it("ensure lazy read", async () => {
//   const fn0 = jest.fn();
//   expect(fn0).toHaveBeenCalledTimes(0);
//   expect(
//     await sflow(lazyStream(fn0)).byLazy(flats()).limit(2).toArray()
//   ).toEqual([0, 1]);
//   expect(fn0).toHaveBeenCalledTimes(1);

//   const fn1 = jest.fn();
//   expect(
//     await sflow(lazyStream(fn1)).byLazy(flats()).limit(3).toArray()
//   ).toEqual([0, 1, 1]);
//   expect(fn1).toHaveBeenCalledTimes(2);
// });