fix: fail clearly on unsupported 32-bit build machines

README.md

@@ -13,6 +13,16 @@ NPM module that builds Windows installers for
 npm install --save-dev electron-winstaller
 ```
 
+## Supported platforms
+
+Installers can be created on x64 and arm64 build machines (Windows, or
+macOS/Linux with Wine and Mono). 32-bit build machines are not supported —
+if you are on 64-bit Windows, make sure you are running 64-bit Node.js.
+
+Apps targeting 32-bit Windows (Electron <= 43) can still be packaged from
+a 64-bit machine; the generated installer runs on 32-bit Windows. Electron
+44 and later do not ship 32-bit Windows builds.
+
 ## Usage
 
 Require the package:

script/select-7z-arch.js

@@ -5,7 +5,12 @@ const os = require('os');
  * Even if we're cross-compiling for a different arch like arm64,
  * we still need to use the 7-Zip executable for the host arch
  */
-const arch = os.arch;
+const arch = os.arch();
+
+if (arch !== 'x64' && arch !== 'arm64') {
+    console.warn('electron-winstaller: 32-bit build machines are not supported; installer creation will fail on this machine.');
+    process.exit(0);
+}
 
 console.log('Selecting 7-Zip for arch ' + arch);
 

spec/assert-supported-arch-spec.ts

@@ -0,0 +1,12 @@
+import test from 'ava';
+import { assertSupportedArch } from '../src/index';
+
+test('throws for 32-bit architectures', (t): void => {
+  t.throws(() => assertSupportedArch('ia32'), { message: '32-bit build machines are not supported' });
+  t.throws(() => assertSupportedArch('arm'), { message: '32-bit build machines are not supported' });
+});
+
+test('does not throw for 64-bit architectures', (t): void => {
+  t.notThrows(() => assertSupportedArch('x64'));
+  t.notThrows(() => assertSupportedArch('arm64'));
+});

src/index.ts

@@ -47,6 +47,19 @@ export function sanitizeAuthors(authors: string): string {
   return authors.replace(/@/g, '');
 }
 
+/**
+ * Asserts that the host architecture is supported. Installer creation
+ * requires an x64 or arm64 build machine; the bundled 7-Zip, NuGet, and
+ * Squirrel tooling cannot run on 32-bit hosts.
+ *
+ * @param arch The host architecture, as reported by `process.arch`
+ */
+export function assertSupportedArch(arch: string = process.arch): void {
+  if (arch !== 'x64' && arch !== 'arm64') {
+    throw new Error('32-bit build machines are not supported');
+  }
+}
+
 function checkIfCommandExists(command: string): Promise<boolean> {
   const checkCommand = os.platform() === 'win32' ? 'where' : 'which';
   return new Promise((resolve) => {
@@ -64,6 +77,8 @@ function checkIfCommandExists(command: string): Promise<boolean> {
  * @see {@link https://github.com/Squirrel/Squirrel.Windows | Squirrel.Windows}
  */
 export async function createWindowsInstaller(options: SquirrelWindowsOptions): Promise<void> {
+  assertSupportedArch();
+
   let useMono = false;
 
   const monoExe = 'mono';