Added vite plugin to expose functions from the bundled IIFE module to the global scope in Google Apps Script

Author: labnol

vite.config.js

@@ -1,22 +1,28 @@
-import { resolve } from 'path';
+import { dirname, resolve } from 'path';
+import { fileURLToPath } from 'url';
 import { defineConfig } from 'vite';
 import { viteStaticCopy } from 'vite-plugin-static-copy';
 
-const viteGoogleAppsScript = () => ({
-  name: 'vite-appscript-exports',
-  generateBundle(outputOptions, bundle) {
-    Object.values(bundle).forEach((bundleChunk) => {
-      const isJavaScriptFile = bundleChunk.fileName.endsWith('.js');
-      const isValidChunk = bundleChunk.type === 'chunk' && bundleChunk.code;
-      const hasExports = bundleChunk.exports?.length > 0;
-      if (isJavaScriptFile && isValidChunk && hasExports) {
-        const { name: libraryNamespace } = outputOptions;
-        const globalFunctions = bundleChunk.exports.map(
-          (fnName) => `const ${fnName} = (...args) => ${libraryNamespace}.${fnName}(...args);`
-        );
-        bundleChunk.code = [bundleChunk.code, ...globalFunctions].join('\n');
-      }
-    });
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+/**
+ * Author: Amit Agarwal (amit@labnol.org)
+ * Description: This is a custom Vite plugin to expose the functions from the bundled IIFE module
+ * to the global scope. This is necessary for Google Apps Script to call
+ * functions like onOpen(e) or other custom functions directly.
+ * @returns {import('vite').Plugin}
+ */
+const viteExposeGasFunctions = () => ({
+  name: 'vite-expose-gas-functions',
+  generateBundle(options, bundle) {
+    const entryChunk = Object.values(bundle).find((chunk) => chunk.type === 'chunk' && chunk.isEntry);
+    if (entryChunk) {
+      const exposureCode = entryChunk.exports
+        .map((fnName) => `function ${fnName}() { return ${options.name}.${fnName}.apply(this, arguments); }`)
+        .join('\n');
+      entryChunk.code += `\n\n${exposureCode}`;
+    }
   },
 });
 
@@ -32,19 +38,18 @@ const targets = [
 ];
 
 export default defineConfig(({ mode }) => ({
-  plugins: [viteGoogleAppsScript(), viteStaticCopy({ targets })],
+  plugins: [viteExposeGasFunctions(), viteStaticCopy({ targets })],
   build: {
-    target: "es2020",
+    target: 'es2020',
     minify: mode !== 'development',
-    outDir: resolve(process.cwd(), 'dist'),
+    outDir: resolve(__dirname, 'dist'),
     lib: {
-      entry: resolve(process.cwd(), 'src/index.js'),
+      entry: resolve(__dirname, 'src/index.js'),
       name: 'app',
       formats: ['iife'],
     },
     rollupOptions: {
       output: {
-        extend: false,
         entryFileNames: 'code.js',
       },
     },