Restore import.meta

Author: hsubox76

packages/firestore/rollup.config.js

@@ -19,18 +19,34 @@ import { version as grpcVersion } from '@grpc/grpc-js/package.json';
 import alias from '@rollup/plugin-alias';
 import json from '@rollup/plugin-json';
 import copy from 'rollup-plugin-copy';
+import replace from 'rollup-plugin-replace';
 import { terser } from 'rollup-plugin-terser';
 import typescriptPlugin from 'rollup-plugin-typescript2';
 import tmp from 'tmp';
 import typescript from 'typescript';
-import replace from 'rollup-plugin-replace';
 
 import { generateBuildTargetReplaceConfig } from '../../scripts/build/rollup_replace_build_target';
 
 import pkg from './package.json';
 
 const util = require('./rollup.shared');
 
+// Customize how import.meta.url is polyfilled in cjs nodejs build. We use it to be able to use require() in esm.
+// It only generates the nodejs version of the polyfill, as opposed to the default polyfill which
+// supports both browser and nodejs. The browser support is unnecessary and doesn't work well with Jest. See https://github.com/firebase/firebase-js-sdk/issues/5687
+function importMetaUrlPolyfillPlugin() {
+  return {
+    name: 'import-meta-url-current-module',
+    resolveImportMeta(property, { moduleId }) {
+      if (property === 'url') {
+        // copied from rollup output
+        return `new (require('url').URL)('file:' + __filename).href`;
+      }
+      return null;
+    }
+  };
+}
+
 const nodePlugins = function () {
   return [
     typescriptPlugin({
@@ -107,7 +123,8 @@ const allBuilds = [
     },
     plugins: [
       ...util.es2017ToEs5Plugins(/* mangled= */ false),
-      replace(generateBuildTargetReplaceConfig('cjs', 2017))
+      replace(generateBuildTargetReplaceConfig('cjs', 2017)),
+      importMetaUrlPolyfillPlugin()
     ],
     external: util.resolveNodeExterns,
     treeshake: {

packages/firestore/src/platform/node/grpc_connection.ts

@@ -35,7 +35,7 @@ import { NodeCallback, nodePromise } from '../../util/node_api';
 import { Deferred } from '../../util/promise';
 
 // TODO: Fetch runtime version from grpc-js/package.json instead
-// when it becomes possible to use require() in Node ESM without hacks.
+// when there's a cleaner way to dynamic require in both Node ESM and CJS
 const grpcVersion = '__GRPC_VERSION__';
 
 const LOG_TAG = 'Connection';