fix: Allow EnableEmbeddedAsarIntegrityValidation when multiple asars are present in app (#124)

- When an application uses multiple asars (`webapp.asar`, `anything.asar`, etc.), `EnableEmbeddedAsarIntegrityValidation` fuse breaks the application due to not all asars having integrity generated for them. Fixes: #116
- **Also fixes bug** to correctly test `makeUniversalApp no asar mode should shim two different app folders`, (it was not having an asar integrity generated for the shimmed asar)

Functionality added:
- Moves all asar integrity generation to **after** all app assets have been merged/shimmed/copied. This allows other asars that were provided to also be scanned and have asar integrity generated for them.
- Extracted common Integrity logic to a single file `integrity.ts`
- Adds unit test for multi-asar apps

.circleci/config.yml

@@ -1,46 +0,0 @@
-step-restore-cache: &step-restore-cache
-  restore_cache:
-    keys:
-      - v1-dependencies-{{ arch }}-{{ checksum "yarn.lock" }}
-      - v1-dependencies-{{ arch }}
-
-steps-test: &steps-test
-  steps:
-    - checkout
-    - *step-restore-cache
-    - run: yarn --frozen-lockfile
-    - save_cache:
-        paths:
-          - node_modules
-        key: v1-dependencies-{{ arch }}-{{ checksum "yarn.lock" }}
-    - run: yarn build
-    - run: yarn test
-
-version: 2.1
-jobs:
-  test:
-    macos:
-      xcode: "12.2.0"
-    <<: *steps-test
-
-  release:
-    docker:
-      - image: circleci/node:14.15
-    steps:
-      - checkout
-      - *step-restore-cache
-      - run: yarn --frozen-lockfile
-      - run: npx semantic-release
-workflows:
-  version: 2
-  test_and_release:
-    jobs:
-      - test
-      - release:
-          requires:
-            - test
-          filters:
-            branches:
-              only:
-                - master
-

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @electron/wg-ecosystem

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"

.github/workflows/add-to-project.yml

@@ -0,0 +1,29 @@
+name: Add to Ecosystem WG Project
+
+on:
+  issues:
+    types:
+      - opened
+  pull_request_target:
+    types:
+      - opened
+
+permissions: {}
+
+jobs:
+  add-to-project:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Generate GitHub App token
+        uses: electron/github-app-auth-action@384fd19694fe7b6dcc9a684746c6976ad78228ae # v1.1.1
+        id: generate-token
+        with:
+          creds: ${{ secrets.ECOSYSTEM_ISSUE_TRIAGE_GH_APP_CREDS }}
+          org: electron
+      - name: Add to Project
+        uses: dsanders11/project-actions/add-item@9c80cd31f58599941c64f74636bea95ba5d46090 # v1.5.1
+        with:
+          field: Opened
+          field-value: ${{ github.event.pull_request.created_at || github.event.issue.created_at }}
+          project-number: 89
+          token: ${{ steps.generate-token.outputs.token }}

.github/workflows/release.yml

@@ -0,0 +1,35 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  test:
+    uses: ./.github/workflows/test.yml
+
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    needs: test
+    environment: npm
+    permissions:
+      id-token: write # for CFA and npm provenance
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          persist-credentials: false
+      - name: Setup Node.js
+        uses: actions/setup-node@1d0ff469b7ec7b3cb9d8673fde0c81c44821de2a # v4.2.0
+        with:
+          node-version: 20.x
+          cache: 'yarn'
+      - name: Install
+        run: yarn install --frozen-lockfile
+      - uses: continuousauth/action@4e8a2573eeb706f6d7300d6a9f3ca6322740b72d # v1.0.5
+        with:
+          project-id: ${{ secrets.CFA_PROJECT_ID }}
+          secret: ${{ secrets.CFA_SECRET }}
+          npm-token: ${{ secrets.NPM_TOKEN }}

.github/workflows/semantic.yml

@@ -0,0 +1,26 @@
+name: "Check Semantic Commit"
+
+on:
+  pull_request:
+    types:
+      - opened
+      - edited
+      - synchronize
+
+permissions:
+  contents: read
+
+jobs:
+  main:
+    permissions:
+      pull-requests: read  # for amannn/action-semantic-pull-request to analyze PRs
+      statuses: write  # for amannn/action-semantic-pull-request to mark status of analyzed PR
+    name: Validate PR Title
+    runs-on: ubuntu-latest
+    steps:
+      - name: semantic-pull-request
+        uses: amannn/action-semantic-pull-request@0723387faaf9b38adef4775cd42cfd5155ed6017 # v5.5.3
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          validateSingleCommit: false

.github/workflows/test.yml

@@ -0,0 +1,44 @@
+name: Test
+
+on:
+  pull_request:
+    branches:
+      - main
+  schedule:
+    - cron: '0 22 * * 3'
+  workflow_call:
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    name: Test
+    strategy:
+      fail-fast: false
+      matrix:
+        node-version:
+          - '20.5'
+          - '18.17'
+          - '16.20'
+    runs-on: macos-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Setup Node.js
+        uses: actions/setup-node@1d0ff469b7ec7b3cb9d8673fde0c81c44821de2a # v4.2.0
+        with:
+          node-version: "${{ matrix.node-version }}"
+          cache: 'yarn'
+      - name: Install (Node.js v18+)
+        if : ${{ matrix.node-version != '16.20' }}
+        run: yarn install --frozen-lockfile
+      - name: Install (Node.js < v18)
+        if : ${{ matrix.node-version == '16.20' }}
+        run: yarn install --frozen-lockfile --ignore-engines
+      - name: Build
+        run: yarn build
+      - name: Lint
+        run: yarn lint
+      - name: Test
+        run: yarn test

.gitignore

@@ -1,3 +1,9 @@
 node_modules
 dist
+entry-asar/*.js*
+entry-asar/*.ts
 *.app
+test/fixtures/apps
+coverage
+docs
+.vscode

.husky/pre-commit

@@ -0,0 +1,4 @@
+#!/usr/bin/env sh
+. "$(dirname -- "$0")/_/husky.sh"
+
+yarn lint-staged

.prettierrc.json

@@ -3,5 +3,13 @@
   "tabWidth": 2,
   "singleQuote": true,
   "printWidth": 100,
-  "parser": "typescript"
+  "parser": "typescript",
+  "overrides": [
+    {
+      "files": ["*.json", "*.jsonc", "*.json5"],
+      "options": {
+        "parser": "json"
+      }
+    }
+  ]
 }

.releaserc.json

@@ -4,6 +4,7 @@
     "@semantic-release/release-notes-generator",
     "@continuous-auth/semantic-release-npm",
     "@semantic-release/github"
-  ]
+  ],
+  "branches": [ "main" ]
 }
 

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Contributors to the Electron project
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -2,11 +2,16 @@
 
 > Create universal macOS Electron applications
 
-[![CircleCI](https://circleci.com/gh/electron/universal/tree/master.svg?style=svg)](https://circleci.com/gh/electron/universal)
+[![Test](https://github.com/electron/universal/actions/workflows/test.yml/badge.svg)](https://github.com/electron/universal/actions/workflows/test.yml)
-
+[![NPM package](https://img.shields.io/npm/v/@electron/universal)](https://npm.im/@electron/universal)
 
 ## Usage
 
+This package takes an x64 app and an arm64 app and glues them together into a
+[Universal macOS binary](https://developer.apple.com/documentation/apple-silicon/building-a-universal-macos-binary).
+
+Note that parameters need to be **absolute** paths.
+
 ```typescript
 import { makeUniversalApp } from '@electron/universal';
 
@@ -17,20 +22,104 @@ await makeUniversalApp({
 });
 ```
 
+## Advanced configuration
+
+The basic usage patterns will work for most apps out of the box. Additional configuration
+options are available for advanced usecases.
+
+### Merging ASAR archives to reduce app size
+
+**Added in [v1.2.0](https://github.com/electron/universal/commit/38ab1c3559e25382957d608e49e624dc72a4409c)**
+
+If you are using ASAR archives to store your Electron app's JavaScript code, you can use the
+`mergeASARs` option to merge your x64 and arm64 ASAR files to reduce the bundle size of
+the output Universal app.
+
+If some files are present in only the x64 app but not the arm64 version (or vice-versa),
+you can exclude them from the merging process by specifying a `minimatch` pattern
+in `singleArchFiles`.
+
+```typescript
+import { makeUniversalApp } from '@electron/universal';
+
+await makeUniversalApp({
+  x64AppPath: 'path/to/App_x64.app',
+  arm64AppPath: 'path/to/App_arm64.app',
+  outAppPath: 'path/to/App_universal.app',
+  mergeASARs: true,
+  singleArchFiles: 'node_modules/some-native-module/lib/binding/Release/**', // if you have files in your asar that are unique to x64 or arm64 apps
+});
+```
+
+If `@electron/universal` detects an architecture-unique file that isn't covered by the
+`singleArchFiles` rule, an error will be thrown.
+
+### Skip lipo for certain binaries in your Universal app
+
+**Added in [1.3.0](https://github.com/electron/universal/commit/01dfb8a9636965fe154192b07934670dd42509f3)**
+
+If your Electron app contains binary resources that are already merged with the
+`lipo` tool, providing a [`minimatch`] pattern to matching files in the `x64ArchFiles`
+parameter will prevent `@electron/universal` from attempting to merge them a second time.
+
+```typescript
+import { makeUniversalApp } from '@electron/universal';
+
+await makeUniversalApp({
+  x64AppPath: 'path/to/App_x64.app',
+  arm64AppPath: 'path/to/App_arm64.app',
+  outAppPath: 'path/to/App_universal.app',
+  mergeASARs: true,
+  x64ArchFiles: '*/electron-helper', // `electron-helper` is a binary merged using `lipo`
+});
+```
+
+If `@electron/universal` detects a lipo'd file that isn't covered by the `x64ArchFiles` rule,
+an error will be thrown.
+
+### Including already codesigned app bundles into your Universal app
+
+**Added in [v1.4.0](https://github.com/electron/universal/commit/b02ce7697fd2a3c2c79e1f6ab6bf7052125865cc)**
+
+By default, the merging process will generate an `ElectronAsarIntegrity` key for
+any `Info.plist` files in your Electron app.
+
+If your Electron app bundles another `.app` that is already signed, you need to use
+the `infoPlistsToIgnore` option to avoid modifying that app's plist.
+
+```typescript
+import { makeUniversalApp } from '@electron/universal';
+
+await makeUniversalApp({
+  x64AppPath: 'path/to/App_x64.app',
+  arm64AppPath: 'path/to/App_arm64.app',
+  outAppPath: 'path/to/App_universal.app',
+  infoPlistsToIgnore: 'my-internal.app/Contents/Info.plist'
+});
+```
+
 ## FAQ
 
 #### The app is twice as big now, why?
 
-Well, a Universal app isn't anything magical.  It is literally the x64 app and
+A Universal app is just the x64 app and the arm64 app glued together into a single application.
-the arm64 app glued together into a single application.  It's twice as big
+It's twice as big because it contains two apps in one.
-because it contains two apps in one.
+
+Merging your ASAR bundles can yield significant app size reductions depending on how large
+your `app.asar` file is.
 
 #### What about native modules?
 
-The way `@electron/universal` works today means you don't need to worry about
+Out of the box, you don't need to worry about building universal versions of your
-things like building universal versions of your native modules.  As long as
+native modules. As long as your x64 and arm64 apps work in isolation, the Universal
-your x64 and arm64 apps work in isolation the Universal app will work as well.
+app will work as well.
+
+Note that if you are using `mergeASARs`, you may need to add architecture-specific
+binary resources to the `singleArchFiles` pattern.
+See [Merging ASARs usage](#merging-asar-archives-to-reduce-app-size) for an example.
 
 #### How do I build my app for Apple silicon in the first place?
 
-Check out the [Electron Apple silicon blog post](https://www.electronjs.org/blog/apple-silicon)
+Check out the [Electron Apple silicon blog post](https://www.electronjs.org/blog/apple-silicon).
+
+[`minimatch`]: https://github.com/isaacs/minimatch?tab=readme-ov-file#features

entry-asar/ambient.d.ts

@@ -0,0 +1,19 @@
+declare namespace NodeJS {
+  interface Process extends EventEmitter {
+    // This is an undocumented private API. It exists.
+    _archPath: string;
+  }
+}
+
+declare module 'electron' {
+  const app: Electron.App;
+
+  namespace Electron {
+    interface App {
+      getAppPath: () => string;
+      setAppPath: (p: string) => void;
+    }
+  }
+
+  export { app };
+}

entry-asar/has-asar.js

@@ -1,7 +0,0 @@
-if (process.arch === 'arm64') {
-  process._archPath = require.resolve('../app-arm64.asar');
-} else {
-  process._archPath = require.resolve('../app-x64.asar');
-}
-
-require(process._archPath);

entry-asar/has-asar.ts

@@ -0,0 +1,27 @@
+import { app } from 'electron';
+import path from 'path';
+
+if (process.arch === 'arm64') {
+  setPaths('arm64');
+} else {
+  setPaths('x64');
+}
+
+function setPaths(platform: string) {
+  // This should return the full path, ending in something like
+  // Notion.app/Contents/Resources/app.asar
+  const appPath = app.getAppPath();
+  const asarFile = `app-${platform}.asar`;
+
+  // Maybe we'll handle this in Electron one day
+  if (path.basename(appPath) === 'app.asar') {
+    const platformAppPath = path.join(path.dirname(appPath), asarFile);
+
+    // This is an undocumented API. It exists.
+    app.setAppPath(platformAppPath);
+  }
+
+  process._archPath = require.resolve(`../${asarFile}`);
+}
+
+require(process._archPath);

entry-asar/no-asar.js

@@ -1,7 +0,0 @@
-if (process.arch === 'arm64') {
-  process._archPath = require.resolve('../app-arm64');
-} else {
-  process._archPath = require.resolve('../app-x64');
-}
-
-require(process._archPath);

entry-asar/no-asar.ts

@@ -0,0 +1,27 @@
+import { app } from 'electron';
+import path from 'path';
+
+if (process.arch === 'arm64') {
+  setPaths('arm64');
+} else {
+  setPaths('x64');
+}
+
+function setPaths(platform: string) {
+  // This should return the full path, ending in something like
+  // Notion.app/Contents/Resources/app
+  const appPath = app.getAppPath();
+  const appFolder = `app-${platform}`;
+
+  // Maybe we'll handle this in Electron one day
+  if (path.basename(appPath) === 'app') {
+    const platformAppPath = path.join(path.dirname(appPath), appFolder);
+
+    // This is an undocumented private API. It exists.
+    app.setAppPath(platformAppPath);
+  }
+
+  process._archPath = require.resolve(`../${appFolder}`);
+}
+
+require(process._archPath);

jest.config.js

@@ -0,0 +1,16 @@
+/** @type {import('ts-jest').JestConfigWithTsJest} */
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  transform: {
+    '^.+\\.ts?$': [
+      'ts-jest',
+      {
+        tsconfig: 'tsconfig.jest.json',
+      },
+    ],
+  },
+  testMatch: ['<rootDir>/test/**/*.spec.ts'],
+  globalSetup: './jest.setup.ts',
+  testTimeout: 10000,
+};

jest.setup.ts

@@ -0,0 +1,51 @@
+import * as fs from 'fs-extra';
+import * as path from 'path';
+import { appsDir, asarsDir, templateApp } from './test/util';
+
+export default async () => {
+  await fs.remove(appsDir);
+  await fs.mkdirp(appsDir);
+  await templateApp('Arm64Asar.app', 'arm64', async (appPath) => {
+    await fs.copy(
+      path.resolve(asarsDir, 'app.asar'),
+      path.resolve(appPath, 'Contents', 'Resources', 'app.asar'),
+    );
+  });
+
+  // contains `extra-file.txt`
+  await templateApp('Arm64AsarExtraFile.app', 'arm64', async (appPath) => {
+    await fs.copy(
+      path.resolve(asarsDir, 'app2.asar'),
+      path.resolve(appPath, 'Contents', 'Resources', 'app.asar'),
+    );
+  });
+
+  await templateApp('X64Asar.app', 'x64', async (appPath) => {
+    await fs.copy(
+      path.resolve(asarsDir, 'app.asar'),
+      path.resolve(appPath, 'Contents', 'Resources', 'app.asar'),
+    );
+  });
+
+  await templateApp('Arm64NoAsar.app', 'arm64', async (appPath) => {
+    await fs.copy(
+      path.resolve(asarsDir, 'app'),
+      path.resolve(appPath, 'Contents', 'Resources', 'app'),
+    );
+  });
+
+  // contains `extra-file.txt`
+  await templateApp('Arm64NoAsarExtraFile.app', 'arm64', async (appPath) => {
+    await fs.copy(
+      path.resolve(asarsDir, 'app2'),
+      path.resolve(appPath, 'Contents', 'Resources', 'app'),
+    );
+  });
+
+  await templateApp('X64NoAsar.app', 'x64', async (appPath) => {
+    await fs.copy(
+      path.resolve(asarsDir, 'app'),
+      path.resolve(appPath, 'Contents', 'Resources', 'app'),
+    );
+  });
+};

package.json

@@ -12,53 +12,63 @@
   ],
   "repository": {
     "type": "git",
-    "url": "https://github.com/electron/universal.git"
+    "url": "git+https://github.com/electron/universal.git"
   },
   "engines": {
-    "node": ">=8.6"
+    "node": ">=16.4"
   },
   "files": [
     "dist/*",
     "entry-asar/*",
+    "!entry-asar/**/*.ts",
     "README.md"
   ],
   "author": "Samuel Attard",
+  "publishConfig": {
+    "provenance": true
+  },
   "scripts": {
-    "build": "tsc && tsc -p tsconfig.esm.json",
+    "build": "tsc -p tsconfig.cjs.json && tsc -p tsconfig.esm.json && tsc -p tsconfig.entry-asar.json",
-    "lint": "prettier --check \"src/**/*.ts\"",
+    "build:docs": "npx typedoc",
+    "lint": "prettier --check \"{src,entry-asar,test}/**/*.ts\" \"*.ts\"",
+    "prettier:write": "prettier --write \"{src,entry-asar,test}/**/*.ts\" \"*.ts\"",
     "prepublishOnly": "npm run build",
-    "test": "exit 0"
+    "test": "jest",
+    "prepare": "husky install"
   },
   "devDependencies": {
-    "@continuous-auth/semantic-release-npm": "^2.0.0",
+    "@electron/get": "^3.0.0",
-    "@types/debug": "^4.1.5",
+    "@types/cross-zip": "^4.0.1",
-    "@types/fs-extra": "^9.0.4",
+    "@types/debug": "^4.1.10",
-    "@types/minimatch": "^3.0.5",
+    "@types/fs-extra": "^11.0.3",
-    "@types/node": "^14.14.7",
+    "@types/jest": "^29.5.7",
-    "@types/plist": "^3.0.2",
+    "@types/minimatch": "^5.1.2",
-    "husky": "^4.3.0",
+    "@types/node": "^20.8.10",
-    "lint-staged": "^10.5.1",
+    "@types/plist": "^3.0.4",
-    "prettier": "^2.1.2",
+    "cross-zip": "^4.0.0",
-    "semantic-release": "^17.2.2",
+    "husky": "^8.0.3",
-    "typescript": "^4.0.5"
+    "jest": "^29.7.0",
+    "lint-staged": "^15.2.10",
+    "prettier": "^3.0.3",
+    "ts-jest": "^29.1.1",
+    "typedoc": "~0.25.13",
+    "typescript": "^5.2.2"
   },
   "dependencies": {
-    "@malept/cross-spawn-promise": "^1.1.0",
+    "@electron/asar": "^3.3.1",
-    "asar": "^3.1.0",
+    "@malept/cross-spawn-promise": "^2.0.0",
     "debug": "^4.3.1",
-    "dir-compare": "^2.4.0",
+    "dir-compare": "^4.2.0",
-    "fs-extra": "^9.0.1",
+    "fs-extra": "^11.1.1",
-    "minimatch": "^3.0.4",
+    "minimatch": "^9.0.3",
-    "plist": "^3.0.4"
+    "plist": "^3.1.0"
-  },
-  "husky": {
-    "hooks": {
-      "pre-commit": "lint-staged"
-    }
   },
   "lint-staged": {
     "*.ts": [
       "prettier --write"
     ]
+  },
+  "resolutions": {
+    "jackspeak": "2.1.1"
   }
 }

src/asar-utils.ts

@@ -1,10 +1,10 @@
-import * as asar from 'asar';
+import asar from '@electron/asar';
 import { execFileSync } from 'child_process';
-import * as crypto from 'crypto';
+import crypto from 'crypto';
-import * as fs from 'fs-extra';
+import fs from 'fs-extra';
-import * as path from 'path';
+import path from 'path';
-import * as minimatch from 'minimatch';
+import { minimatch } from 'minimatch';
-import * as os from 'os';
+import os from 'os';
 import { d } from './debug';
 
 const LIPO = 'lipo';
@@ -25,12 +25,15 @@ export type MergeASARsOptions = {
 // See: https://github.com/apple-opensource-mirror/llvmCore/blob/0c60489d96c87140db9a6a14c6e82b15f5e5d252/include/llvm/Object/MachOFormat.h#L108-L112
 const MACHO_MAGIC = new Set([
   // 32-bit Mach-O
-  0xfeedface,
+  0xfeedface, 0xcefaedfe,
-  0xcefaedfe,
 
   // 64-bit Mach-O
-  0xfeedfacf,
+  0xfeedfacf, 0xcffaedfe,
-  0xcffaedfe,
+]);
+
+const MACHO_UNIVERSAL_MAGIC = new Set([
+  // universal
+  0xcafebabe, 0xbebafeca,
 ]);
 
 export const detectAsarMode = async (appPath: string) => {
@@ -81,8 +84,10 @@ export const mergeASARs = async ({
 }: MergeASARsOptions): Promise<void> => {
   d(`merging ${x64AsarPath} and ${arm64AsarPath}`);
 
-  const x64Files = new Set(asar.listPackage(x64AsarPath).map(toRelativePath));
+  const x64Files = new Set(asar.listPackage(x64AsarPath, { isPack: false }).map(toRelativePath));
-  const arm64Files = new Set(asar.listPackage(arm64AsarPath).map(toRelativePath));
+  const arm64Files = new Set(
+    asar.listPackage(arm64AsarPath, { isPack: false }).map(toRelativePath),
+  );
 
   //
   // Build set of unpacked directories and files
@@ -147,6 +152,13 @@ export const mergeASARs = async ({
       continue;
     }
 
+    if (
+      MACHO_UNIVERSAL_MAGIC.has(x64Content.readUInt32LE(0)) &&
+      MACHO_UNIVERSAL_MAGIC.has(arm64Content.readUInt32LE(0))
+    ) {
+      continue;
+    }
+
     if (!MACHO_MAGIC.has(x64Content.readUInt32LE(0))) {
       throw new Error(`Can't reconcile two non-macho files ${file}`);
     }
@@ -195,8 +207,15 @@ export const mergeASARs = async ({
 
     const resolvedUnpack = Array.from(unpackedFiles).map((file) => path.join(x64Dir, file));
 
+    let unpack: string | undefined;
+    if (resolvedUnpack.length > 1) {
+      unpack = `{${resolvedUnpack.join(',')}}`;
+    } else if (resolvedUnpack.length === 1) {
+      unpack = resolvedUnpack[0];
+    }
+
     await asar.createPackageWithOptions(x64Dir, outputAsarPath, {
-      unpack: `{${resolvedUnpack.join(',')}}`,
+      unpack,
     });
 
     d('done merging');

src/debug.ts

@@ -1,3 +1,3 @@
-import * as debug from 'debug';
+import debug from 'debug';
 
 export const d = debug('electron-universal');

src/file-utils.ts

@@ -45,7 +45,7 @@ export const getAllAppFiles = async (appPath: string): Promise<AppFile[]> => {
           throw e;
         }
       }
-      if (p.includes('app.asar')) {
+      if (p.endsWith('.asar')) {
         fileType = AppFileType.APP_CODE;
       } else if (fileOutput.startsWith(MACHO_PREFIX)) {
         fileType = AppFileType.MACHO;

src/index.ts

@@ -1,49 +1,76 @@
 import { spawn } from '@malept/cross-spawn-promise';
-import * as asar from 'asar';
+import * as asar from '@electron/asar';
-import * as crypto from 'crypto';
 import * as fs from 'fs-extra';
-import * as minimatch from 'minimatch';
+import { minimatch } from 'minimatch';
 import * as os from 'os';
 import * as path from 'path';
 import * as plist from 'plist';
 import * as dircompare from 'dir-compare';
 
 import { AppFile, AppFileType, getAllAppFiles } from './file-utils';
-import { AsarMode, detectAsarMode, generateAsarIntegrity, mergeASARs } from './asar-utils';
+import { AsarMode, detectAsarMode, mergeASARs } from './asar-utils';
 import { sha } from './sha';
 import { d } from './debug';
+import { computeIntegrityData } from './integrity';
 
-type MakeUniversalOpts = {
+/**
+ * Options to pass into the {@link makeUniversalApp} function.
+ *
+ * Requires absolute paths for input x64 and arm64 apps and an absolute path to the
+ * output universal app.
+ */
+export type MakeUniversalOpts = {
   /**
-   * Absolute file system path to the x64 version of your application.  E.g. /Foo/bar/MyApp_x64.app
+   * Absolute file system path to the x64 version of your application (e.g. `/Foo/bar/MyApp_x64.app`).
    */
   x64AppPath: string;
   /**
-   * Absolute file system path to the arm64 version of your application.  E.g. /Foo/bar/MyApp_arm64.app
+   * Absolute file system path to the arm64 version of your application (e.g. `/Foo/bar/MyApp_arm64.app`).
    */
   arm64AppPath: string;
   /**
-   * Absolute file system path you want the universal app to be written to.  E.g. /Foo/var/MyApp_universal.app
+   * Absolute file system path you want the universal app to be written to (e.g. `/Foo/var/MyApp_universal.app`).
    *
-   * If this file exists it will be overwritten ONLY if "force" is set to true
+   * If this file exists on disk already, it will be overwritten ONLY if {@link MakeUniversalOpts.force} is set to `true`.
    */
   outAppPath: string;
   /**
-   * Forcefully overwrite any existing files that are in the way of generating the universal application
+   * Forcefully overwrite any existing files that are in the way of generating the universal application.
+   *
+   * @defaultValue `false`
    */
-  force: boolean;
+  force?: boolean;
   /**
    * Merge x64 and arm64 ASARs into one.
+   *
+   * @defaultValue `false`
    */
   mergeASARs?: boolean;
   /**
-   * Minimatch pattern of paths that are allowed to be present in one of the ASAR files, but not in the other.
+   * If {@link MakeUniversalOpts.mergeASARs} is enabled, this property provides a
+   * {@link https://github.com/isaacs/minimatch?tab=readme-ov-file#features | minimatch}
+   * pattern of paths that are allowed to be present in one of the ASAR files, but not in the other.
+   *
    */
   singleArchFiles?: string;
   /**
-   * Minimatch pattern of binaries that are expected to be the same x64 binary in both of the ASAR files.
+   * A {@link https://github.com/isaacs/minimatch?tab=readme-ov-file#features | minimatch}
+   * pattern of binaries that are expected to be the same x64 binary in both
+   *
+   * Use this if your application contains binaries that have already been merged into a universal file
+   * using the `lipo` tool.
+   *
+   * @see Apple's {@link https://developer.apple.com/documentation/apple-silicon/building-a-universal-macos-binary | Building a universal macOS binary} documentation
+   *
    */
   x64ArchFiles?: string;
+  /**
+   * A {@link https://github.com/isaacs/minimatch?tab=readme-ov-file#features | minimatch} pattern of `Info.plist`
+   * paths that should not receive an injected `ElectronAsarIntegrity` value.
+   *
+   * Use this if your application contains another bundle that's already signed.
+   */
+  infoPlistsToIgnore?: string;
 };
 
 const dupedFiles = (files: AppFile[]) =>
@@ -130,7 +157,7 @@ export const makeUniversalApp = async (opts: MakeUniversalOpts): Promise<void> =
         );
       }
     }
-
+    const knownMergedMachOFiles = new Set();
     for (const machOFile of x64Files.filter((f) => f.type === AppFileType.MACHO)) {
       const first = await fs.realpath(path.resolve(tmpApp, machOFile.relativePath));
       const second = await fs.realpath(path.resolve(opts.arm64AppPath, machOFile.relativePath));
@@ -167,6 +194,7 @@ export const makeUniversalApp = async (opts: MakeUniversalOpts): Promise<void> =
         '-output',
         await fs.realpath(path.resolve(tmpApp, machOFile.relativePath)),
       ]);
+      knownMergedMachOFiles.add(machOFile.relativePath);
     }
 
     /**
@@ -182,8 +210,18 @@ export const makeUniversalApp = async (opts: MakeUniversalOpts): Promise<void> =
         path.resolve(opts.arm64AppPath, 'Contents', 'Resources', 'app'),
         { compareSize: true, compareContent: true },
       );
+      const differences = comparison.diffSet!.filter((difference) => difference.state !== 'equal');
+      d(`Found ${differences.length} difference(s) between the x64 and arm64 folders`);
+      const nonMergedDifferences = differences.filter(
+        (difference) =>
+          !difference.name1 ||
+          !knownMergedMachOFiles.has(
+            path.join('Contents', 'Resources', 'app', difference.relativePath, difference.name1),
+          ),
+      );
+      d(`After discluding MachO files merged with lipo ${nonMergedDifferences.length} remain.`);
 
-      if (!comparison.same) {
+      if (nonMergedDifferences.length > 0) {
         d('x64 and arm64 app folders are different, creating dynamic entry ASAR');
         await fs.move(
           path.resolve(tmpApp, 'Contents', 'Resources', 'app'),
@@ -214,9 +252,6 @@ export const makeUniversalApp = async (opts: MakeUniversalOpts): Promise<void> =
       }
     }
 
-    const generatedIntegrity: Record<string, { algorithm: 'SHA256'; hash: string }> = {};
-    let didSplitAsar = false;
-
     /**
      * If we have an ASAR we just need to check if the two "app.asar" files have the same hash,
      * if they are, same as above, we can leave one there and call it a day.  If they're different
@@ -234,8 +269,6 @@ export const makeUniversalApp = async (opts: MakeUniversalOpts): Promise<void> =
         outputAsarPath: output,
         singleArchFiles: opts.singleArchFiles,
       });
-
-      generatedIntegrity['Resources/app.asar'] = generateAsarIntegrity(output);
     } else if (x64AsarMode === AsarMode.HAS_ASAR) {
       d('checking if the x64 and arm64 asars are identical');
       const x64AsarSha = await sha(path.resolve(tmpApp, 'Contents', 'Resources', 'app.asar'));
@@ -244,7 +277,6 @@ export const makeUniversalApp = async (opts: MakeUniversalOpts): Promise<void> =
       );
 
       if (x64AsarSha !== arm64AsarSha) {
-        didSplitAsar = true;
         d('x64 and arm64 asars are different');
         const x64AsarPath = path.resolve(tmpApp, 'Contents', 'Resources', 'app-x64.asar');
         await fs.move(path.resolve(tmpApp, 'Contents', 'Resources', 'app.asar'), x64AsarPath);
@@ -292,18 +324,13 @@ export const makeUniversalApp = async (opts: MakeUniversalOpts): Promise<void> =
         await fs.writeJson(path.resolve(entryAsar, 'package.json'), pj);
         const asarPath = path.resolve(tmpApp, 'Contents', 'Resources', 'app.asar');
         await asar.createPackage(entryAsar, asarPath);
-
-        generatedIntegrity['Resources/app.asar'] = generateAsarIntegrity(asarPath);
-        generatedIntegrity['Resources/app-x64.asar'] = generateAsarIntegrity(x64AsarPath);
-        generatedIntegrity['Resources/app-arm64.asar'] = generateAsarIntegrity(arm64AsarPath);
       } else {
         d('x64 and arm64 asars are the same');
-        generatedIntegrity['Resources/app.asar'] = generateAsarIntegrity(
-          path.resolve(tmpApp, 'Contents', 'Resources', 'app.asar'),
-        );
       }
     }
 
+    const generatedIntegrity = await computeIntegrityData(path.join(tmpApp, 'Contents'));
+
     const plistFiles = x64Files.filter((f) => f.type === AppFileType.INFO_PLIST);
     for (const plistFile of plistFiles) {
       const x64PlistPath = path.resolve(opts.x64AppPath, plistFile.relativePath);
@@ -321,7 +348,12 @@ export const makeUniversalApp = async (opts: MakeUniversalOpts): Promise<void> =
         );
       }
 
-      const mergedPlist = { ...x64Plist, ElectronAsarIntegrity: generatedIntegrity };
+      const injectAsarIntegrity =
+        !opts.infoPlistsToIgnore ||
+        minimatch(plistFile.relativePath, opts.infoPlistsToIgnore, { matchBase: true });
+      const mergedPlist = injectAsarIntegrity
+        ? { ...x64Plist, ElectronAsarIntegrity: generatedIntegrity }
+        : { ...x64Plist };
 
       await fs.writeFile(path.resolve(tmpApp, plistFile.relativePath), plist.build(mergedPlist));
     }

src/integrity.ts

@@ -0,0 +1,51 @@
+import * as fs from 'fs-extra';
+import path from 'path';
+import { AppFileType, getAllAppFiles } from './file-utils';
+import { sha } from './sha';
+import { generateAsarIntegrity } from './asar-utils';
+
+type IntegrityMap = {
+  [filepath: string]: string;
+};
+
+export interface HeaderHash {
+  algorithm: 'SHA256';
+  hash: string;
+}
+
+export interface AsarIntegrity {
+  [key: string]: HeaderHash;
+}
+
+export async function computeIntegrityData(contentsPath: string): Promise<AsarIntegrity> {
+  const root = await fs.realpath(contentsPath);
+
+  const resourcesRelativePath = 'Resources';
+  const resourcesPath = path.resolve(root, resourcesRelativePath);
+
+  const resources = await getAllAppFiles(resourcesPath);
+  const resourceAsars = resources
+    .filter((file) => file.type === AppFileType.APP_CODE)
+    .reduce<IntegrityMap>(
+      (prev, file) => ({
+        ...prev,
+        [path.join(resourcesRelativePath, file.relativePath)]: path.join(
+          resourcesPath,
+          file.relativePath,
+        ),
+      }),
+      {},
+    );
+
+  // sort to produce constant result
+  const allAsars = Object.entries(resourceAsars).sort(([name1], [name2]) =>
+    name1.localeCompare(name2),
+  );
+  const hashes = await Promise.all(allAsars.map(async ([, from]) => generateAsarIntegrity(from)));
+  const asarIntegrity: AsarIntegrity = {};
+  for (let i = 0; i < allAsars.length; i++) {
+    const [asar] = allAsars[i];
+    asarIntegrity[asar] = hashes[i];
+  }
+  return asarIntegrity;
+}

src/sha.ts

@@ -1,16 +1,13 @@
 import * as fs from 'fs-extra';
 import * as crypto from 'crypto';
+import { pipeline } from 'stream/promises';
+
 import { d } from './debug';
 
 export const sha = async (filePath: string) => {
   d('hashing', filePath);
   const hash = crypto.createHash('sha256');
   hash.setEncoding('hex');
-  const fileStream = fs.createReadStream(filePath);
+  await pipeline(fs.createReadStream(filePath), hash);
-  fileStream.pipe(hash);
-  await new Promise((resolve, reject) => {
-    fileStream.on('end', () => resolve());
-    fileStream.on('error', (err) => reject(err));
-  });
   return hash.read();
 };

test/__snapshots__/index.spec.ts.snap

@@ -0,0 +1,722 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`makeUniversalApp asar mode should correctly merge two identical asars 1`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+        ],
+        "hash": "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+      },
+      "size": 64,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should correctly merge two identical asars 2`] = `
+{
+  "Contents/Info.plist": {
+    "Resources/app.asar": {
+      "algorithm": "SHA256",
+      "hash": "85fff474383bd8df11cd9c5784e8fcd1525af71ff140a8a882e1dc9d5b39fcbf",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should create a shim if asars are different between architectures 1`] = `
+{
+  "files": {
+    "extra-file.txt": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "b8f261b95f81761658c8875b33a68001d8750fd898f447373bf6347e779bc3de",
+        ],
+        "hash": "b8f261b95f81761658c8875b33a68001d8750fd898f447373bf6347e779bc3de",
+      },
+      "size": 15,
+    },
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+        ],
+        "hash": "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+      },
+      "size": 64,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should create a shim if asars are different between architectures 2`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+        ],
+        "hash": "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+      },
+      "size": 64,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should create a shim if asars are different between architectures 3`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "b7e5f58d3c0fddc1a57d1279a7f19a34a01784f4036920d4b60a1e33f6d1635b",
+        ],
+        "hash": "b7e5f58d3c0fddc1a57d1279a7f19a34a01784f4036920d4b60a1e33f6d1635b",
+      },
+      "size": 1068,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "2873266521e41d58d02e7acfbbbdb046edfa04b6ce262b8987de8e8548671fc7",
+        ],
+        "hash": "2873266521e41d58d02e7acfbbbdb046edfa04b6ce262b8987de8e8548671fc7",
+      },
+      "size": 33,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should create a shim if asars are different between architectures 4`] = `
+{
+  "Contents/Info.plist": {
+    "Resources/app-arm64.asar": {
+      "algorithm": "SHA256",
+      "hash": "71db54541357128943df64d54480a22d0cdf4c283f2044f48101fb1fc6e6fb2d",
+    },
+    "Resources/app-x64.asar": {
+      "algorithm": "SHA256",
+      "hash": "85fff474383bd8df11cd9c5784e8fcd1525af71ff140a8a882e1dc9d5b39fcbf",
+    },
+    "Resources/app.asar": {
+      "algorithm": "SHA256",
+      "hash": "b62aaaed07ff72dc33da1720d900e0443c060285ef374ce1bdaef1d4f28b5fe4",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should generate AsarIntegrity for all asars in the application 1`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+        ],
+        "hash": "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+      },
+      "size": 66,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+    "private": {
+      "files": {
+        "var": {
+          "files": {
+            "app": {
+              "files": {
+                "file.txt": {
+                  "link": "private/var/file.txt",
+                },
+              },
+            },
+            "file.txt": {
+              "integrity": {
+                "algorithm": "SHA256",
+                "blockSize": 4194304,
+                "blocks": [
+                  "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+                ],
+                "hash": "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+              },
+              "size": 11,
+            },
+          },
+        },
+      },
+    },
+    "var": {
+      "link": "private/var",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should generate AsarIntegrity for all asars in the application 2`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+        ],
+        "hash": "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+      },
+      "size": 66,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+    "private": {
+      "files": {
+        "var": {
+          "files": {
+            "app": {
+              "files": {
+                "file.txt": {
+                  "link": "private/var/file.txt",
+                },
+              },
+            },
+            "file.txt": {
+              "integrity": {
+                "algorithm": "SHA256",
+                "blockSize": 4194304,
+                "blocks": [
+                  "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+                ],
+                "hash": "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+              },
+              "size": 11,
+            },
+          },
+        },
+      },
+    },
+    "var": {
+      "link": "private/var",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should generate AsarIntegrity for all asars in the application 3`] = `
+{
+  "Contents/Info.plist": {
+    "Resources/app.asar": {
+      "algorithm": "SHA256",
+      "hash": "7e6af4d00f4cc737eff922e2b386128a269f80887b79a011022f1276bdbe7832",
+    },
+    "Resources/webbapp.asar": {
+      "algorithm": "SHA256",
+      "hash": "7e6af4d00f4cc737eff922e2b386128a269f80887b79a011022f1276bdbe7832",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should merge two different asars when \`mergeASARs\` is enabled 1`] = `
+{
+  "files": {
+    "extra-file.txt": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "b8f261b95f81761658c8875b33a68001d8750fd898f447373bf6347e779bc3de",
+        ],
+        "hash": "b8f261b95f81761658c8875b33a68001d8750fd898f447373bf6347e779bc3de",
+      },
+      "size": 15,
+    },
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+        ],
+        "hash": "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+      },
+      "size": 64,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should merge two different asars when \`mergeASARs\` is enabled 2`] = `
+{
+  "Contents/Info.plist": {
+    "Resources/app.asar": {
+      "algorithm": "SHA256",
+      "hash": "71db54541357128943df64d54480a22d0cdf4c283f2044f48101fb1fc6e6fb2d",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should not inject ElectronAsarIntegrity into \`infoPlistsToIgnore\` 1`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+        ],
+        "hash": "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+      },
+      "size": 66,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+    "private": {
+      "files": {
+        "var": {
+          "files": {
+            "app": {
+              "files": {
+                "file.txt": {
+                  "link": "private/var/file.txt",
+                },
+              },
+            },
+            "file.txt": {
+              "integrity": {
+                "algorithm": "SHA256",
+                "blockSize": 4194304,
+                "blocks": [
+                  "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+                ],
+                "hash": "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+              },
+              "size": 11,
+            },
+          },
+        },
+      },
+    },
+    "var": {
+      "link": "private/var",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should not inject ElectronAsarIntegrity into \`infoPlistsToIgnore\` 2`] = `
+{
+  "Contents/Info.plist": undefined,
+  "Contents/Resources/SubApp-1.app/Contents/Info.plist": undefined,
+}
+`;
+
+exports[`makeUniversalApp asar mode should shim asars with different unpacked dirs 1`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+        ],
+        "hash": "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+      },
+      "size": 66,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+    "private": {
+      "files": {
+        "var": {
+          "files": {
+            "app": {
+              "files": {
+                "file.txt": {
+                  "link": "private/var/file.txt",
+                  "unpacked": true,
+                },
+              },
+            },
+            "file.txt": {
+              "integrity": {
+                "algorithm": "SHA256",
+                "blockSize": 4194304,
+                "blocks": [
+                  "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+                ],
+                "hash": "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+              },
+              "size": 11,
+              "unpacked": true,
+            },
+          },
+        },
+      },
+    },
+    "var": {
+      "link": "private/var",
+      "unpacked": true,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should shim asars with different unpacked dirs 2`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+        ],
+        "hash": "0f6311dac07f0876c436ce2be042eb88c96e17eaf140b39627cf720dd87ad5b8",
+      },
+      "size": 66,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+    "private": {
+      "files": {
+        "var": {
+          "files": {
+            "app": {
+              "files": {
+                "file.txt": {
+                  "link": "private/var/file.txt",
+                },
+              },
+            },
+            "file.txt": {
+              "integrity": {
+                "algorithm": "SHA256",
+                "blockSize": 4194304,
+                "blocks": [
+                  "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+                ],
+                "hash": "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+              },
+              "size": 11,
+            },
+          },
+        },
+      },
+    },
+    "var": {
+      "link": "private/var",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should shim asars with different unpacked dirs 3`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "b7e5f58d3c0fddc1a57d1279a7f19a34a01784f4036920d4b60a1e33f6d1635b",
+        ],
+        "hash": "b7e5f58d3c0fddc1a57d1279a7f19a34a01784f4036920d4b60a1e33f6d1635b",
+      },
+      "size": 1068,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "2873266521e41d58d02e7acfbbbdb046edfa04b6ce262b8987de8e8548671fc7",
+        ],
+        "hash": "2873266521e41d58d02e7acfbbbdb046edfa04b6ce262b8987de8e8548671fc7",
+      },
+      "size": 33,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp asar mode should shim asars with different unpacked dirs 4`] = `
+[
+  {
+    "content": "hello world",
+    "name": "private/var/file.txt",
+  },
+]
+`;
+
+exports[`makeUniversalApp asar mode should shim asars with different unpacked dirs 5`] = `
+{
+  "Contents/Info.plist": {
+    "Resources/app-arm64.asar": {
+      "algorithm": "SHA256",
+      "hash": "d06a628e759f54def7ff8785a077b3a3d756882cb84ee99e9725966226e1f195",
+    },
+    "Resources/app-x64.asar": {
+      "algorithm": "SHA256",
+      "hash": "7e6af4d00f4cc737eff922e2b386128a269f80887b79a011022f1276bdbe7832",
+    },
+    "Resources/app.asar": {
+      "algorithm": "SHA256",
+      "hash": "b62aaaed07ff72dc33da1720d900e0443c060285ef374ce1bdaef1d4f28b5fe4",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp force packages successfully if \`out\` bundle already exists and \`force\` is \`true\` 1`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+        ],
+        "hash": "8c8cefe616b330a70980c457e479360417a320f53f484d34df65227ce3add026",
+      },
+      "size": 64,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+        ],
+        "hash": "d6226276d47adc7aa20e6c46e842e258f5157313074a035051a89612acdd6be3",
+      },
+      "size": 41,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp force packages successfully if \`out\` bundle already exists and \`force\` is \`true\` 2`] = `
+{
+  "Contents/Info.plist": {
+    "Resources/app.asar": {
+      "algorithm": "SHA256",
+      "hash": "85fff474383bd8df11cd9c5784e8fcd1525af71ff140a8a882e1dc9d5b39fcbf",
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp no asar mode should correctly merge two identical app folders 1`] = `
+[
+  "index.js",
+  {
+    "content": "{
+  "name": "app",
+  "main": "index.js"
+}",
+    "name": "package.json",
+  },
+]
+`;
+
+exports[`makeUniversalApp no asar mode should correctly merge two identical app folders 2`] = `
+{
+  "Contents/Info.plist": {},
+}
+`;
+
+exports[`makeUniversalApp no asar mode should shim two different app folders 1`] = `
+{
+  "files": {
+    "index.js": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "f1e14240f7c833900fca84fabc2f0ff27084efdf1c5b228b015515de3f8fa28e",
+        ],
+        "hash": "f1e14240f7c833900fca84fabc2f0ff27084efdf1c5b228b015515de3f8fa28e",
+      },
+      "size": 1063,
+    },
+    "package.json": {
+      "integrity": {
+        "algorithm": "SHA256",
+        "blockSize": 4194304,
+        "blocks": [
+          "2873266521e41d58d02e7acfbbbdb046edfa04b6ce262b8987de8e8548671fc7",
+        ],
+        "hash": "2873266521e41d58d02e7acfbbbdb046edfa04b6ce262b8987de8e8548671fc7",
+      },
+      "size": 33,
+    },
+  },
+}
+`;
+
+exports[`makeUniversalApp no asar mode should shim two different app folders 2`] = `
+[
+  "private/var/i-aint-got-no-rhythm.bin",
+]
+`;
+
+exports[`makeUniversalApp no asar mode should shim two different app folders 3`] = `
+[
+  "index.js",
+  {
+    "content": "{
+  "name": "app",
+  "main": "index.js"
+}",
+    "name": "package.json",
+  },
+  {
+    "content": "hello world",
+    "name": "private/var/file.txt",
+  },
+  "private/var/i-aint-got-no-rhythm.bin",
+]
+`;
+
+exports[`makeUniversalApp no asar mode should shim two different app folders 4`] = `
+[
+  "index.js",
+  {
+    "content": "{
+  "name": "app",
+  "main": "index.js"
+}",
+    "name": "package.json",
+  },
+  {
+    "content": "hello world",
+    "name": "private/var/file.txt",
+  },
+  "private/var/hello-world.bin",
+]
+`;
+
+exports[`makeUniversalApp no asar mode should shim two different app folders 5`] = `
+{
+  "Contents/Info.plist": {
+    "Resources/app.asar": {
+      "algorithm": "SHA256",
+      "hash": "27433ee3e34b3b0dabb29d18d40646126e80c56dbce8c4bb2adef7278b5a46c0",
+    },
+  },
+}
+`;

test/asar-utils.spec.ts

@@ -0,0 +1,28 @@
+import * as path from 'path';
+
+import { AsarMode, detectAsarMode, generateAsarIntegrity } from '../src/asar-utils';
+
+const asarsPath = path.resolve(__dirname, 'fixtures', 'asars');
+const appsPath = path.resolve(__dirname, 'fixtures', 'apps');
+
+describe('asar-utils', () => {
+  describe('detectAsarMode', () => {
+    it('should correctly detect an asar enabled app', async () => {
+      expect(await detectAsarMode(path.resolve(appsPath, 'Arm64Asar.app'))).toBe(AsarMode.HAS_ASAR);
+    });
+
+    it('should correctly detect an app without an asar', async () => {
+      expect(await detectAsarMode(path.resolve(appsPath, 'Arm64NoAsar.app'))).toBe(
+        AsarMode.NO_ASAR,
+      );
+    });
+  });
+
+  describe('generateAsarIntegrity', () => {
+    it('should deterministically hash an asar header', async () => {
+      expect(generateAsarIntegrity(path.resolve(asarsPath, 'app.asar')).hash).toEqual(
+        '85fff474383bd8df11cd9c5784e8fcd1525af71ff140a8a882e1dc9d5b39fcbf',
+      );
+    });
+  });
+});

test/file-utils.spec.ts

@@ -0,0 +1,61 @@
+import * as path from 'path';
+
+import { AppFile, AppFileType, getAllAppFiles } from '../src/file-utils';
+
+const appsPath = path.resolve(__dirname, 'fixtures', 'apps');
+
+describe('file-utils', () => {
+  describe('getAllAppFiles', () => {
+    let asarFiles: AppFile[];
+    let noAsarFiles: AppFile[];
+
+    beforeAll(async () => {
+      asarFiles = await getAllAppFiles(path.resolve(appsPath, 'Arm64Asar.app'));
+      noAsarFiles = await getAllAppFiles(path.resolve(appsPath, 'Arm64NoAsar.app'));
+    });
+
+    it('should correctly identify plist files', async () => {
+      expect(asarFiles.find((f) => f.relativePath === 'Contents/Info.plist')?.type).toBe(
+        AppFileType.INFO_PLIST,
+      );
+    });
+
+    it('should correctly identify asar files as app code', async () => {
+      expect(asarFiles.find((f) => f.relativePath === 'Contents/Resources/app.asar')?.type).toBe(
+        AppFileType.APP_CODE,
+      );
+    });
+
+    it('should correctly identify non-asar code files as plain text', async () => {
+      expect(
+        noAsarFiles.find((f) => f.relativePath === 'Contents/Resources/app/index.js')?.type,
+      ).toBe(AppFileType.PLAIN);
+    });
+
+    it('should correctly identify the Electron binary as Mach-O', async () => {
+      expect(noAsarFiles.find((f) => f.relativePath === 'Contents/MacOS/Electron')?.type).toBe(
+        AppFileType.MACHO,
+      );
+    });
+
+    it('should correctly identify the Electron Framework as Mach-O', async () => {
+      expect(
+        noAsarFiles.find(
+          (f) =>
+            f.relativePath ===
+            'Contents/Frameworks/Electron Framework.framework/Versions/A/Electron Framework',
+        )?.type,
+      ).toBe(AppFileType.MACHO);
+    });
+
+    it('should correctly identify the v8 context snapshot', async () => {
+      expect(
+        noAsarFiles.find(
+          (f) =>
+            f.relativePath ===
+            'Contents/Frameworks/Electron Framework.framework/Versions/A/Resources/v8_context_snapshot.arm64.bin',
+        )?.type,
+      ).toBe(AppFileType.SNAPSHOT);
+    });
+  });
+});

test/fixtures/asars/app/index.js

@@ -0,0 +1,2 @@
+console.log('I am an app folder', process.arch);
+process.exit(0);

test/fixtures/asars/app/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "app",
+  "main": "index.js"
+}

test/fixtures/asars/app2/extra-file.txt

@@ -0,0 +1 @@
+erick was here!

test/fixtures/asars/app2/index.js

@@ -0,0 +1,2 @@
+console.log('I am an app.asar', process.arch);
+process.exit(0);

test/fixtures/asars/app2/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "app",
+  "main": "index.js"
+}

test/fixtures/tohash

@@ -0,0 +1 @@
+hello there

test/index.spec.ts

@@ -0,0 +1,283 @@
+import * as fs from 'fs-extra';
+import * as path from 'path';
+
+import { makeUniversalApp } from '../dist/cjs/index';
+import { createTestApp, templateApp, VERIFY_APP_TIMEOUT, verifyApp } from './util';
+import { createPackage, createPackageWithOptions } from '@electron/asar';
+
+const appsPath = path.resolve(__dirname, 'fixtures', 'apps');
+const appsOutPath = path.resolve(__dirname, 'fixtures', 'apps', 'out');
+
+// See `jest.setup.ts` for app fixture setup process
+describe('makeUniversalApp', () => {
+  afterEach(async () => {
+    await fs.emptyDir(appsOutPath);
+  });
+
+  it('throws an error if asar is only detected in one arch', async () => {
+    const out = path.resolve(appsOutPath, 'Error.app');
+    await expect(
+      makeUniversalApp({
+        x64AppPath: path.resolve(appsPath, 'X64Asar.app'),
+        arm64AppPath: path.resolve(appsPath, 'Arm64NoAsar.app'),
+        outAppPath: out,
+      }),
+    ).rejects.toThrow(
+      'Both the x64 and arm64 versions of your application need to have been built with the same asar settings (enabled vs disabled)',
+    );
+  });
+
+  it.todo('works for lipo binary resources');
+
+  describe('force', () => {
+    it('throws an error if `out` bundle already exists and `force` is `false`', async () => {
+      const out = path.resolve(appsOutPath, 'Error.app');
+      await fs.mkdirp(out);
+      await expect(
+        makeUniversalApp({
+          x64AppPath: path.resolve(appsPath, 'X64Asar.app'),
+          arm64AppPath: path.resolve(appsPath, 'Arm64Asar.app'),
+          outAppPath: out,
+        }),
+      ).rejects.toThrow(/The out path ".*" already exists and force is not set to true/);
+    });
+
+    it(
+      'packages successfully if `out` bundle already exists and `force` is `true`',
+      async () => {
+        const out = path.resolve(appsOutPath, 'Error.app');
+        await fs.mkdirp(out);
+        await makeUniversalApp({
+          x64AppPath: path.resolve(appsPath, 'X64Asar.app'),
+          arm64AppPath: path.resolve(appsPath, 'Arm64Asar.app'),
+          outAppPath: out,
+          force: true,
+        });
+        await verifyApp(out);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+  });
+
+  describe('asar mode', () => {
+    it(
+      'should correctly merge two identical asars',
+      async () => {
+        const out = path.resolve(appsOutPath, 'MergedAsar.app');
+        await makeUniversalApp({
+          x64AppPath: path.resolve(appsPath, 'X64Asar.app'),
+          arm64AppPath: path.resolve(appsPath, 'Arm64Asar.app'),
+          outAppPath: out,
+        });
+        await verifyApp(out);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+
+    it(
+      'should create a shim if asars are different between architectures',
+      async () => {
+        const out = path.resolve(appsOutPath, 'ShimmedAsar.app');
+        await makeUniversalApp({
+          x64AppPath: path.resolve(appsPath, 'X64Asar.app'),
+          arm64AppPath: path.resolve(appsPath, 'Arm64AsarExtraFile.app'),
+          outAppPath: out,
+        });
+        await verifyApp(out);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+
+    it(
+      'should merge two different asars when `mergeASARs` is enabled',
+      async () => {
+        const out = path.resolve(appsOutPath, 'MergedAsar.app');
+        await makeUniversalApp({
+          x64AppPath: path.resolve(appsPath, 'X64Asar.app'),
+          arm64AppPath: path.resolve(appsPath, 'Arm64AsarExtraFile.app'),
+          outAppPath: out,
+          mergeASARs: true,
+          singleArchFiles: 'extra-file.txt',
+        });
+        await verifyApp(out);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+
+    it(
+      'throws an error if `mergeASARs` is enabled and `singleArchFiles` is missing a unique file',
+      async () => {
+        const out = path.resolve(appsOutPath, 'Error.app');
+        await expect(
+          makeUniversalApp({
+            x64AppPath: path.resolve(appsPath, 'X64Asar.app'),
+            arm64AppPath: path.resolve(appsPath, 'Arm64AsarExtraFile.app'),
+            outAppPath: out,
+            mergeASARs: true,
+            singleArchFiles: 'bad-rule',
+          }),
+        ).rejects.toThrow(/Detected unique file "extra-file\.txt"/);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+
+    it(
+      'should not inject ElectronAsarIntegrity into `infoPlistsToIgnore`',
+      async () => {
+        const arm64AppPath = await templateApp('Arm64-1.app', 'arm64', async (appPath) => {
+          const { testPath } = await createTestApp('Arm64-1');
+          await createPackage(testPath, path.resolve(appPath, 'Contents', 'Resources', 'app.asar'));
+          await templateApp('SubApp-1.app', 'arm64', async (subArm64AppPath) => {
+            await fs.move(
+              subArm64AppPath,
+              path.resolve(appPath, 'Contents', 'Resources', path.basename(subArm64AppPath)),
+            );
+          });
+        });
+        const x64AppPath = await templateApp('X64-1.app', 'x64', async (appPath) => {
+          const { testPath } = await createTestApp('X64-1');
+          await createPackage(testPath, path.resolve(appPath, 'Contents', 'Resources', 'app.asar'));
+          await templateApp('SubApp-1.app', 'x64', async (subArm64AppPath) => {
+            await fs.move(
+              subArm64AppPath,
+              path.resolve(appPath, 'Contents', 'Resources', path.basename(subArm64AppPath)),
+            );
+          });
+        });
+        const outAppPath = path.resolve(appsOutPath, 'UnmodifiedPlist.app');
+        await makeUniversalApp({
+          x64AppPath,
+          arm64AppPath,
+          outAppPath,
+          mergeASARs: true,
+          infoPlistsToIgnore: 'SubApp-1.app/Contents/Info.plist',
+        });
+        await verifyApp(outAppPath);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+
+    // TODO: Investigate if this should even be allowed.
+    // Current logic detects all unpacked files as APP_CODE, which doesn't seem correct since it could also be a macho file requiring lipo
+    // https://github.com/electron/universal/blob/d90d573ccf69a5b14b91aa818c8b97e0e6840399/src/file-utils.ts#L48-L49
+    it.skip(
+      'should shim asars with different unpacked dirs',
+      async () => {
+        const arm64AppPath = await templateApp('UnpackedArm64.app', 'arm64', async (appPath) => {
+          const { testPath } = await createTestApp('UnpackedAppArm64');
+          await createPackageWithOptions(
+            testPath,
+            path.resolve(appPath, 'Contents', 'Resources', 'app.asar'),
+            {
+              unpackDir: 'var',
+              unpack: '*.txt',
+            },
+          );
+        });
+
+        const x64AppPath = await templateApp('UnpackedX64.app', 'x64', async (appPath) => {
+          const { testPath } = await createTestApp('UnpackedAppX64');
+          await createPackageWithOptions(
+            testPath,
+            path.resolve(appPath, 'Contents', 'Resources', 'app.asar'),
+            {},
+          );
+        });
+
+        const outAppPath = path.resolve(appsOutPath, 'UnpackedDir.app');
+        await makeUniversalApp({
+          x64AppPath,
+          arm64AppPath,
+          outAppPath,
+        });
+        await verifyApp(outAppPath);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+
+    it(
+      'should generate AsarIntegrity for all asars in the application',
+      async () => {
+        const { testPath } = await createTestApp('app-2');
+        const testAsarPath = path.resolve(appsOutPath, 'app-2.asar');
+        await createPackage(testPath, testAsarPath);
+
+        const arm64AppPath = await templateApp('Arm64-2.app', 'arm64', async (appPath) => {
+          await fs.copyFile(
+            testAsarPath,
+            path.resolve(appPath, 'Contents', 'Resources', 'app.asar'),
+          );
+          await fs.copyFile(
+            testAsarPath,
+            path.resolve(appPath, 'Contents', 'Resources', 'webapp.asar'),
+          );
+        });
+        const x64AppPath = await templateApp('X64-2.app', 'x64', async (appPath) => {
+          await fs.copyFile(
+            testAsarPath,
+            path.resolve(appPath, 'Contents', 'Resources', 'app.asar'),
+          );
+          await fs.copyFile(
+            testAsarPath,
+            path.resolve(appPath, 'Contents', 'Resources', 'webbapp.asar'),
+          );
+        });
+        const outAppPath = path.resolve(appsOutPath, 'MultipleAsars.app');
+        await makeUniversalApp({
+          x64AppPath,
+          arm64AppPath,
+          outAppPath,
+          mergeASARs: true,
+        });
+        await verifyApp(outAppPath);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+  });
+
+  describe('no asar mode', () => {
+    it(
+      'should correctly merge two identical app folders',
+      async () => {
+        const out = path.resolve(appsOutPath, 'MergedNoAsar.app');
+        await makeUniversalApp({
+          x64AppPath: path.resolve(appsPath, 'X64NoAsar.app'),
+          arm64AppPath: path.resolve(appsPath, 'Arm64NoAsar.app'),
+          outAppPath: out,
+        });
+        await verifyApp(out);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+
+    it(
+      'should shim two different app folders',
+      async () => {
+        const arm64AppPath = await templateApp('ShimArm64.app', 'arm64', async (appPath) => {
+          const { testPath } = await createTestApp('shimArm64', {
+            'i-aint-got-no-rhythm.bin': 'boomshakalaka',
+          });
+          await fs.copy(testPath, path.resolve(appPath, 'Contents', 'Resources', 'app'));
+        });
+
+        const x64AppPath = await templateApp('ShimX64.app', 'x64', async (appPath) => {
+          const { testPath } = await createTestApp('shimX64', { 'hello-world.bin': 'Hello World' });
+          await fs.copy(testPath, path.resolve(appPath, 'Contents', 'Resources', 'app'));
+        });
+
+        const outAppPath = path.resolve(appsOutPath, 'ShimNoAsar.app');
+        await makeUniversalApp({
+          x64AppPath,
+          arm64AppPath,
+          outAppPath,
+        });
+        await verifyApp(outAppPath);
+      },
+      VERIFY_APP_TIMEOUT,
+    );
+  });
+
+  // TODO: Add tests for
+  // * different app dirs with different macho files
+  // * identical app dirs with universal macho files
+});

test/sha.spec.ts

@@ -0,0 +1,11 @@
+import * as path from 'path';
+
+import { sha } from '../src/sha';
+
+describe('sha', () => {
+  it('should correctly hash a file', async () => {
+    expect(await sha(path.resolve(__dirname, 'fixtures', 'tohash'))).toEqual(
+      '12998c017066eb0d2a70b94e6ed3192985855ce390f321bbdb832022888bd251',
+    );
+  });
+});

test/util.ts

@@ -0,0 +1,181 @@
+import { downloadArtifact } from '@electron/get';
+import { spawn } from '@malept/cross-spawn-promise';
+import * as zip from 'cross-zip';
+import * as fs from 'fs-extra';
+import * as path from 'path';
+import plist from 'plist';
+import * as fileUtils from '../dist/cjs/file-utils';
+import { getRawHeader } from '@electron/asar';
+
+// We do a LOT of verifications in `verifyApp` 😅
+// exec universal binary -> verify ALL asars -> verify ALL app dirs -> verify ALL asar integrity entries
+// plus some tests create fixtures at runtime
+export const VERIFY_APP_TIMEOUT = 80 * 1000;
+
+export const asarsDir = path.resolve(__dirname, 'fixtures', 'asars');
+export const appsDir = path.resolve(__dirname, 'fixtures', 'apps');
+export const appsOutPath = path.resolve(appsDir, 'out');
+
+export const verifyApp = async (appPath: string) => {
+  await ensureUniversal(appPath);
+
+  const resourcesDir = path.resolve(appPath, 'Contents', 'Resources');
+  const resourcesDirContents = await fs.readdir(resourcesDir);
+
+  // sort for consistent result
+  const asars = resourcesDirContents.filter((p) => p.endsWith('.asar')).sort();
+  for await (const asar of asars) {
+    // verify header
+    const asarFs = getRawHeader(path.resolve(resourcesDir, asar));
+    expect(removeUnstableProperties(asarFs.header)).toMatchSnapshot();
+  }
+
+  // check all app and unpacked dirs (incl. shimmed)
+  const dirsToSnapshot = [
+    'app',
+    'app.asar.unpacked',
+    'app-x64',
+    'app-x64.asar.unpacked',
+    'app-arm64',
+    'app-arm64.asar.unpacked',
+  ];
+  const appDirs = resourcesDirContents
+    .filter((p) => dirsToSnapshot.includes(path.basename(p)))
+    .sort();
+  for await (const dir of appDirs) {
+    await verifyFileTree(path.resolve(resourcesDir, dir));
+  }
+
+  const allFiles = await fileUtils.getAllAppFiles(appPath);
+  const infoPlists = allFiles
+    .filter(
+      (appFile) =>
+        appFile.type === fileUtils.AppFileType.INFO_PLIST &&
+        // These are test app fixtures, no need to snapshot within `TestApp.app/Contents/Frameworks`
+        !appFile.relativePath.includes(path.join('Contents', 'Frameworks')),
+    )
+    .map((af) => af.relativePath)
+    .sort();
+
+  const integrityMap: Record<string, string> = {};
+  const integrity = await Promise.all(
+    infoPlists.map((ip) => extractAsarIntegrity(path.resolve(appPath, ip))),
+  );
+  for (let i = 0; i < integrity.length; i++) {
+    const relativePath = infoPlists[i];
+    const asarIntegrity = integrity[i];
+    integrityMap[relativePath] = asarIntegrity;
+  }
+  expect(integrityMap).toMatchSnapshot();
+};
+
+// note: `infoPlistsToIgnore` will not have integrity in sub-app plists
+const extractAsarIntegrity = async (infoPlist: string) => {
+  const { ElectronAsarIntegrity: integrity, ...otherData } = plist.parse(
+    await fs.readFile(infoPlist, 'utf-8'),
+  ) as any;
+  return integrity;
+};
+
+export const verifyFileTree = async (dirPath: string) => {
+  const dirFiles = await fileUtils.getAllAppFiles(dirPath);
+  const files = dirFiles.map((file) => {
+    const it = path.join(dirPath, file.relativePath);
+    const name = toSystemIndependentPath(file.relativePath);
+    if (it.endsWith('.txt') || it.endsWith('.json')) {
+      return { name, content: fs.readFileSync(it, 'utf-8') };
+    }
+    return name;
+  });
+  expect(files).toMatchSnapshot();
+};
+
+export const ensureUniversal = async (app: string) => {
+  const exe = path.resolve(app, 'Contents', 'MacOS', 'Electron');
+  const result = await spawn(exe);
+  expect(result).toContain('arm64');
+  const result2 = await spawn('arch', ['-x86_64', exe]);
+  expect(result2).toContain('x64');
+};
+
+export const toSystemIndependentPath = (s: string): string => {
+  return path.sep === '/' ? s : s.replace(/\\/g, '/');
+};
+
+export const removeUnstableProperties = (data: any) => {
+  return JSON.parse(
+    JSON.stringify(data, (name, value) => {
+      if (name === 'offset') {
+        return undefined;
+      }
+      return value;
+    }),
+  );
+};
+
+/**
+ * Directory structure:
+ * testName
+ * ├── private
+ * │   └── var
+ * │       ├── app
+ * │       │   └── file.txt -> ../file.txt
+ * │       └── file.txt
+ * └── var -> private/var
+ * ├── index.js
+ * ├── package.json
+ */
+export const createTestApp = async (
+  testName: string | undefined,
+  additionalFiles: Record<string, string> = {},
+) => {
+  const outDir = (testName || 'app') + Math.floor(Math.random() * 100); // tests run in parallel, randomize dir suffix to prevent naming collisions
+  const testPath = path.join(appsDir, outDir);
+  await fs.remove(testPath);
+
+  await fs.copy(path.join(asarsDir, 'app'), testPath);
+
+  const privateVarPath = path.join(testPath, 'private', 'var');
+  const varPath = path.join(testPath, 'var');
+
+  await fs.mkdir(privateVarPath, { recursive: true });
+  await fs.symlink(path.relative(testPath, privateVarPath), varPath);
+
+  const files = {
+    'file.txt': 'hello world',
+    ...additionalFiles,
+  };
+  for await (const [filename, fileData] of Object.entries(files)) {
+    const originFilePath = path.join(varPath, filename);
+    await fs.writeFile(originFilePath, fileData);
+  }
+  const appPath = path.join(varPath, 'app');
+  await fs.mkdirp(appPath);
+  await fs.symlink('../file.txt', path.join(appPath, 'file.txt'));
+
+  return {
+    testPath,
+    varPath,
+    appPath,
+  };
+};
+
+export const templateApp = async (
+  name: string,
+  arch: string,
+  modify: (appPath: string) => Promise<void>,
+) => {
+  const electronZip = await downloadArtifact({
+    artifactName: 'electron',
+    version: '27.0.0',
+    platform: 'darwin',
+    arch,
+  });
+  const appPath = path.resolve(appsDir, name);
+  zip.unzipSync(electronZip, appsDir);
+  await fs.rename(path.resolve(appsDir, 'Electron.app'), appPath);
+  await fs.remove(path.resolve(appPath, 'Contents', 'Resources', 'default_app.asar'));
+  await modify(appPath);
+
+  return appPath;
+};

tsconfig.cjs.json

@@ -0,0 +1,4 @@
+{
+  "extends": "./tsconfig.json",
+  "include": ["src"]
+}

tsconfig.entry-asar.json

@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "entry-asar",
+  },
+  "include": [
+    "entry-asar"
+  ],
+  "exclude": []
+}

tsconfig.esm.json

@@ -3,5 +3,6 @@
   "compilerOptions": {
     "module": "esnext",
     "outDir": "dist/esm"
-  }
+  },
+  "include": ["src"]
 }

tsconfig.jest.json

@@ -0,0 +1,11 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "esnext",
+    "outDir": "dist/esm",
+    "types": [
+      "jest"
+    ]
+  },
+  "include": ["src"]
+}

tsconfig.json

@@ -13,9 +13,11 @@
     ],
     "allowSyntheticDefaultImports": true,
     "moduleResolution": "node",
+    "esModuleInterop": true,
     "declaration": true
   },
   "include": [
-    "src"
+    "src",
+    "entry-asar"
   ]
 }

typedoc.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "https://typedoc.org/schema.json",
+  "entryPoints": ["./src/index.ts"],
+  "excludeInternal": true,
+  "sort": ["source-order"]
+}