test(NODE-6920): esm bundles do not have top-level await

etc/rollup/rollup-plugin-require-rewriter/require_rewriter.mjs

@@ -1,3 +1,4 @@
+import assert from 'node:assert/strict';
 import MagicString from 'magic-string';
 
 const CRYPTO_IMPORT_ESM_SRC = `import { randomBytes as nodejsRandomBytes } from 'crypto';`;
@@ -11,7 +12,10 @@ const CODE_TO_REPLACE = `const nodejsRandomBytes = (() => {
     }
 })();`;
 
-export function requireRewriter({ isBrowser = false } = {}) {
+/** @param {{ target: 'browser' | 'node'}} configuration - destination information that changes the replacement syntax used. */
+export function requireRewriter({ target }) {
+  assert.match(target, /^(node|browser)$/, 'target must be either "node" or "browser"');
+
   return {
     /**
      * Take the compiled source code input; types are expected to already have been removed
@@ -35,7 +39,7 @@ export function requireRewriter({ isBrowser = false } = {}) {
 
       // MagicString lets us edit the source code and still generate an accurate source map
       const magicString = new MagicString(code);
-      magicString.overwrite(start, end, isBrowser ? BROWSER_ESM_SRC : CRYPTO_IMPORT_ESM_SRC);
+      magicString.overwrite(start, end, target === 'browser' ? BROWSER_ESM_SRC : CRYPTO_IMPORT_ESM_SRC);
 
       return {
         code: magicString.toString(),

package.json

@@ -79,7 +79,7 @@
   "exports": {
     "browser": {
       "types": "./bson.d.ts",
-      "default": "./lib/bson.browser.mjs"
+      "default": "./lib/bson.mjs"
     },
     "react-native": "./lib/bson.rn.cjs",
     "default": {

rollup.config.mjs

@@ -57,18 +57,18 @@ const config = [
     input,
     plugins: [
       typescript(tsConfig),
-      requireRewriter({ isBrowser: true }),
+      requireRewriter({ target: 'browser' }),
       nodeResolve({ resolveOnly: [] })
     ],
     output: {
-      file: 'lib/bson.browser.mjs',
+      file: 'lib/bson.mjs',
       format: 'esm',
       sourcemap: true
     }
   },
   {
     input,
-    plugins: [typescript(tsConfig), requireRewriter(), nodeResolve({ resolveOnly: [] })],
+    plugins: [typescript(tsConfig), requireRewriter({ target: 'node' }), nodeResolve({ resolveOnly: [] })],
     output: {
       file: 'lib/bson.node.mjs',
       format: 'esm',

test/node/exports.test.ts

@@ -3,6 +3,7 @@ import * as BSON from '../register-bson';
 import { sorted, byStrings } from './tools/utils';
 import { readFile } from 'fs/promises';
 import { resolve } from 'path';
+import * as child_process from 'node:child_process';
 
 const EXPECTED_EXPORTS = [
   // This is our added web indicator not a real export but a small exception for this test.
@@ -41,6 +42,7 @@ const EXPECTED_EXPORTS = [
 ];
 
 const EXPECTED_EJSON_EXPORTS = ['parse', 'stringify', 'serialize', 'deserialize'];
+const NODE_MAJOR = Number(process.versions.node.split('.')[0]);
 
 describe('bson entrypoint', () => {
   it('should export all and only the expected keys in expected_exports', () => {
@@ -96,4 +98,32 @@ describe('bson entrypoint', () => {
       expect(pkg).nested.property('exports.default.types', './bson.d.ts');
     });
   });
+
+  function testSyncESMImport(name, module) {
+    return () => {
+      const child = child_process.spawnSync(
+        'node',
+        ['--experimental-print-required-tla', '--print', `require('${module}')`],
+        { encoding: 'utf-8' }
+      );
+
+      expect(
+        child.status,
+        `expected to be able to 'require' to import the ${name} ESM because there should be no top-level await:\n` +
+          child.stderr
+      ).to.equal(0);
+    };
+  }
+
+  const itFn = NODE_MAJOR < 22 ? it.skip : it;
+
+  itFn(
+    'browser bundle does not use top-level await',
+    testSyncESMImport('browser', './lib/bson.mjs')
+  );
+
+  itFn(
+    'node bundle does not use top-level await',
+    testSyncESMImport('node', './lib/bson.node.mjs')
+  );
 });

test/node/release.test.ts

@@ -11,14 +11,16 @@ const REQUIRED_FILES = [
   'README.md',
   'bson.d.ts',
   'etc/prepare.js',
-  'lib/bson.bundle.js',
   'lib/bson.bundle.js.map',
-  'lib/bson.cjs',
+  'lib/bson.bundle.js',
   'lib/bson.cjs.map',
-  'lib/bson.mjs',
+  'lib/bson.cjs',
   'lib/bson.mjs.map',
-  'lib/bson.rn.cjs',
+  'lib/bson.mjs',
+  'lib/bson.node.mjs.map',
+  'lib/bson.node.mjs',
   'lib/bson.rn.cjs.map',
+  'lib/bson.rn.cjs',
   'package.json',
   'src/binary.ts',
   'src/bson_value.ts',