bun.sh/test/bun.js/node-stream.test.js

import { expect, describe, it } from "bun:test";
import {
  Readable,
  Writable,
  Duplex,
  Transform,
  PassThrough,
} from "node:stream";

describe("Readable", () => {
  it("should be able to be piped via .pipe", () => {
    const readable = new Readable({
      _read() {
        this.push("Hello World!");
        this.push(null);
      },
    });

    const writable = new Writable({
      _write(chunk, encoding, callback) {
        expect(chunk.toString()).toBe("Hello World!");
        callback();
      },
    });

    readable.pipe(writable);
  });
});

describe("Duplex", () => {
  it("should allow subclasses to be derived via .call() on class", () => {
    function Subclass(opts) {
      if (!(this instanceof Subclass)) return new Subclass(opts);
      Duplex.call(this, opts);
    }

    Object.setPrototypeOf(Subclass.prototype, Duplex.prototype);
    Object.setPrototypeOf(Subclass, Duplex);

    const subclass = new Subclass();
    expect(subclass instanceof Duplex).toBe(true);
  });
});

describe("Transform", () => {
  it("should allow subclasses to be derived via .call() on class", () => {
    function Subclass(opts) {
      if (!(this instanceof Subclass)) return new Subclass(opts);
      Transform.call(this, opts);
    }

    Object.setPrototypeOf(Subclass.prototype, Transform.prototype);
    Object.setPrototypeOf(Subclass, Transform);

    const subclass = new Subclass();
    expect(subclass instanceof Transform).toBe(true);
  });
});

describe("PassThrough", () => {
  it("should allow subclasses to be derived via .call() on class", () => {
    function Subclass(opts) {
      if (!(this instanceof Subclass)) return new Subclass(opts);
      PassThrough.call(this, opts);
    }

    Object.setPrototypeOf(Subclass.prototype, PassThrough.prototype);
    Object.setPrototypeOf(Subclass, PassThrough);

    const subclass = new Subclass();
    expect(subclass instanceof PassThrough).toBe(true);
  });
});