bun.sh/test/bun.js/concat.test.js

import { describe, it, expect } from "bun:test";
import { gcTick } from "./gc";
import { concatArrayBuffers } from "bun";

describe("concat", () => {
  function polyfill(chunks) {
    var size = 0;
    for (const chunk of chunks) {
      size += chunk.byteLength;
    }
    var buffer = new ArrayBuffer(size);
    var view = new Uint8Array(buffer);
    var offset = 0;
    for (const chunk of chunks) {
      view.set(chunk, offset);
      offset += chunk.byteLength;
    }
    return buffer;
  }

  function concatToString(chunks) {
    return Array.from(new Uint8Array(concatArrayBuffers(chunks))).join("");
  }

  function polyfillToString(chunks) {
    return Array.from(new Uint8Array(polyfill(chunks))).join("");
  }

  it("works with one element", () => {
    expect(concatToString([new Uint8Array([123])])).toBe(
      polyfillToString([new Uint8Array([123])]),
    );
  });

  it("works with two elements", () => {
    expect(
      concatToString([Uint8Array.from([123]), Uint8Array.from([456])]),
    ).toBe(polyfillToString([Uint8Array.from([123]), Uint8Array.from([456])]));
  });

  it("works with mix of ArrayBuffer and TypedArray elements", () => {
    expect(
      concatToString([Uint8Array.from([123]).buffer, Uint8Array.from([456])]),
    ).toBe(polyfillToString([Uint8Array.from([123]), Uint8Array.from([456])]));
  });
});