Add jest exception (#5858)

packages/firestore/rollup.config.js

@@ -35,19 +35,30 @@ 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.
+// nodejs. The browser support doesn't work well with Jest.
 // See https://github.com/firebase/firebase-js-sdk/issues/5687
+// Although this is a cjs Node build and shouldn't require the browser option,
+// Vercel apps using this break on deployment, but work in local development.
+// See https://github.com/firebase/firebase-js-sdk/issues/5823
 function importMetaUrlPolyfillPlugin(filename) {
   return {
     name: 'import-meta-url-current-module',
     resolveImportMeta(property, { moduleId }) {
       if (property === 'url') {
-        // copied from rollup output
+        // Added a check for Jest (see issue 5687 linked above)
+        // See https://jestjs.io/docs/environment-variables - apparently
+        // these are not always both set.
+        const JEST_CHECK =
+          `typeof process !== 'undefined' && process.env !== undefined` +
+          ` && (process.env.JEST_WORKER_ID !== undefined || ` +
+          `process.env.NODE_ENV === 'test')`;
+        // Copied from rollup output
         return (
-          "(typeof document === 'undefined' ? new (require('url').URL)" +
-          "('file:' + __filename).href : (document.currentScript && " +
+          `((typeof document === 'undefined' || (${JEST_CHECK})) ?` +
+          ` new (require('url').URL)` +
+          `('file:' + __filename).href : (document.currentScript && ` +
           `document.currentScript.src || new URL('${filename}', ` +
-          'document.baseURI).href))'
+          `document.baseURI).href))`
         );
       }
       return null;