chore(get): factor out nw download logic (#1020)

### Description of Changes

- Factor out NW.js download logic

Author: ayushmanchhabra

README.md

@@ -293,8 +293,7 @@ nwbuild({
 - chore(cicd): use `google-github-actions/release-please-action` to automate publishing to npm, updating changelog and creating releases
 - chore(cli): migrate from `yargs` to `commander`
 - chore(get): verify sha checksum for downloads
-- chore(util): factor out nw file paths finder
-- chore(get): factor out nwjs downloader
+- chore(util): factor out file paths as constant variables
 - chore(get): factor out ffmpeg downloader
 - chore(get): factor out node headers downloader
 - chore(bld): factor out core build step

src/get/nw.js

@@ -0,0 +1,60 @@
+import path from "node:path";
+
+import request from "./request.js";
+
+/**
+ * Download NW.js binary.
+ *
+ * @param  {string}          downloadUrl  - Download server
+ * @param  {string}          version      - Runtime version
+ * @param  {string}          flavor       - Runtime build flavor
+ * @param  {string}          platform     - NW supported platform
+ * @param  {string}          arch         - NW supported architecture
+ * @param  {string}          cacheDir     - Directory to store NW binaries
+ * @return {Promise<string>}              - path of compressed file which contains NW.js binaries.
+ */
+export default async function nw(downloadUrl, version, flavor, platform, arch, cacheDir) {
+
+  /**
+   * Name of directory which contains NW.js binaries.
+   *
+   * @type {string}
+   */
+  const nwDir = [
+    `nwjs`,
+    flavor === 'sdk' ? '-sdk' : '',
+    `-v${version}-${platform}-${arch}`,
+  ].join('');
+
+  /**
+   * Name of compressed file which contains NW.js binaries.
+   *
+   * @type {string}
+   */
+  const nwFile = [
+    nwDir,
+    platform === 'linux' ? "tar.gz" : "zip"
+  ].join('.');
+
+  /**
+   * URL to download specific NW.js binary from.
+   *
+   * @type {string}
+   */
+  const url = [
+    downloadUrl,
+    `v${version}`,
+    nwFile,
+  ].join('/');
+
+  /**
+   * Absolute path of compressed file which contains NW.js binaries.
+   */
+  const nwFileAbs = path.resolve(
+    cacheDir,
+    nwFile
+  );
+  await request(url, nwFileAbs);
+
+  return nwFileAbs;
+}

src/get/nw.test.js

@@ -0,0 +1,29 @@
+import fs from "node:fs";
+import process from "node:process";
+
+import { afterEach, describe, expect, it } from "vitest";
+
+import util from "../util.js";
+
+import nw from "./nw.js";
+
+describe("get/nw", function () {
+
+  let nwFile = '';
+
+  afterEach(function () {
+    fs.promises.rm(nwFile, { recursive: true, force: true });
+  });
+
+  it("downloades a NW.js Linux tarball or Windows/MacOS zip", async function () {
+    nwFile = await nw(
+      "https://dl.nwjs.io",
+      "0.83.0",
+      "sdk",
+      util.PLATFORM_KV[process.platform],
+      util.ARCH_KV[process.arch],
+      "./test/fixture"
+    );
+    expect(util.fileExists(nwFile)).resolves.toBe(true);
+  }, Infinity);
+});