Index: frontend/node_modules/react-dev-utils/browsersHelper.js
===================================================================
--- frontend/node_modules/react-dev-utils/browsersHelper.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
+++ frontend/node_modules/react-dev-utils/browsersHelper.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
@@ -0,0 +1,95 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+'use strict';
+
+const browserslist = require('browserslist');
+const chalk = require('chalk');
+const os = require('os');
+const prompts = require('prompts');
+const pkgUp = require('pkg-up');
+const fs = require('fs');
+
+const defaultBrowsers = {
+  production: ['>0.2%', 'not dead', 'not op_mini all'],
+  development: [
+    'last 1 chrome version',
+    'last 1 firefox version',
+    'last 1 safari version',
+  ],
+};
+
+function shouldSetBrowsers(isInteractive) {
+  if (!isInteractive) {
+    return Promise.resolve(true);
+  }
+
+  const question = {
+    type: 'confirm',
+    name: 'shouldSetBrowsers',
+    message:
+      chalk.yellow("We're unable to detect target browsers.") +
+      `\n\nWould you like to add the defaults to your ${chalk.bold(
+        'package.json'
+      )}?`,
+    initial: true,
+  };
+
+  return prompts(question).then(answer => answer.shouldSetBrowsers);
+}
+
+function checkBrowsers(dir, isInteractive, retry = true) {
+  const current = browserslist.loadConfig({ path: dir });
+  if (current != null) {
+    return Promise.resolve(current);
+  }
+
+  if (!retry) {
+    return Promise.reject(
+      new Error(
+        chalk.red(
+          'As of react-scripts >=2 you must specify targeted browsers.'
+        ) +
+          os.EOL +
+          `Please add a ${chalk.underline(
+            'browserslist'
+          )} key to your ${chalk.bold('package.json')}.`
+      )
+    );
+  }
+
+  return shouldSetBrowsers(isInteractive).then(shouldSetBrowsers => {
+    if (!shouldSetBrowsers) {
+      return checkBrowsers(dir, isInteractive, false);
+    }
+
+    return (
+      pkgUp({ cwd: dir })
+        .then(filePath => {
+          if (filePath == null) {
+            return Promise.reject();
+          }
+          const pkg = JSON.parse(fs.readFileSync(filePath));
+          pkg['browserslist'] = defaultBrowsers;
+          fs.writeFileSync(filePath, JSON.stringify(pkg, null, 2) + os.EOL);
+
+          browserslist.clearCaches();
+          console.log();
+          console.log(
+            `${chalk.green('Set target browsers:')} ${chalk.cyan(
+              defaultBrowsers.join(', ')
+            )}`
+          );
+          console.log();
+        })
+        // Swallow any error
+        .catch(() => {})
+        .then(() => checkBrowsers(dir, isInteractive, false))
+    );
+  });
+}
+
+module.exports = { defaultBrowsers, checkBrowsers };