Index: frontend/node_modules/react-dev-utils/WebpackDevServerUtils.js
===================================================================
--- frontend/node_modules/react-dev-utils/WebpackDevServerUtils.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
+++ frontend/node_modules/react-dev-utils/WebpackDevServerUtils.js	(revision 9af201e94b5a79beb92a30858fc54de4bc3b9449)
@@ -0,0 +1,443 @@
+/**
+ * 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 address = require('address');
+const fs = require('fs');
+const path = require('path');
+const url = require('url');
+const chalk = require('chalk');
+const detect = require('detect-port-alt');
+const isRoot = require('is-root');
+const prompts = require('prompts');
+const clearConsole = require('./clearConsole');
+const formatWebpackMessages = require('./formatWebpackMessages');
+const getProcessForPort = require('./getProcessForPort');
+const forkTsCheckerWebpackPlugin = require('./ForkTsCheckerWebpackPlugin');
+
+const isInteractive = process.stdout.isTTY;
+
+function prepareUrls(protocol, host, port, pathname = '/') {
+  const formatUrl = hostname =>
+    url.format({
+      protocol,
+      hostname,
+      port,
+      pathname,
+    });
+  const prettyPrintUrl = hostname =>
+    url.format({
+      protocol,
+      hostname,
+      port: chalk.bold(port),
+      pathname,
+    });
+
+  const isUnspecifiedHost = host === '0.0.0.0' || host === '::';
+  let prettyHost, lanUrlForConfig, lanUrlForTerminal;
+  if (isUnspecifiedHost) {
+    prettyHost = 'localhost';
+    try {
+      // This can only return an IPv4 address
+      lanUrlForConfig = address.ip();
+      if (lanUrlForConfig) {
+        // Check if the address is a private ip
+        // https://en.wikipedia.org/wiki/Private_network#Private_IPv4_address_spaces
+        if (
+          /^10[.]|^172[.](1[6-9]|2[0-9]|3[0-1])[.]|^192[.]168[.]/.test(
+            lanUrlForConfig
+          )
+        ) {
+          // Address is private, format it for later use
+          lanUrlForTerminal = prettyPrintUrl(lanUrlForConfig);
+        } else {
+          // Address is not private, so we will discard it
+          lanUrlForConfig = undefined;
+        }
+      }
+    } catch (_e) {
+      // ignored
+    }
+  } else {
+    prettyHost = host;
+  }
+  const localUrlForTerminal = prettyPrintUrl(prettyHost);
+  const localUrlForBrowser = formatUrl(prettyHost);
+  return {
+    lanUrlForConfig,
+    lanUrlForTerminal,
+    localUrlForTerminal,
+    localUrlForBrowser,
+  };
+}
+
+function printInstructions(appName, urls, useYarn) {
+  console.log();
+  console.log(`You can now view ${chalk.bold(appName)} in the browser.`);
+  console.log();
+
+  if (urls.lanUrlForTerminal) {
+    console.log(
+      `  ${chalk.bold('Local:')}            ${urls.localUrlForTerminal}`
+    );
+    console.log(
+      `  ${chalk.bold('On Your Network:')}  ${urls.lanUrlForTerminal}`
+    );
+  } else {
+    console.log(`  ${urls.localUrlForTerminal}`);
+  }
+
+  console.log();
+  console.log('Note that the development build is not optimized.');
+  console.log(
+    `To create a production build, use ` +
+      `${chalk.cyan(`${useYarn ? 'yarn' : 'npm run'} build`)}.`
+  );
+  console.log();
+}
+
+function createCompiler({
+  appName,
+  config,
+  urls,
+  useYarn,
+  useTypeScript,
+  webpack,
+}) {
+  // "Compiler" is a low-level interface to webpack.
+  // It lets us listen to some events and provide our own custom messages.
+  let compiler;
+  try {
+    compiler = webpack(config);
+  } catch (err) {
+    console.log(chalk.red('Failed to compile.'));
+    console.log();
+    console.log(err.message || err);
+    console.log();
+    process.exit(1);
+  }
+
+  // "invalid" event fires when you have changed a file, and webpack is
+  // recompiling a bundle. WebpackDevServer takes care to pause serving the
+  // bundle, so if you refresh, it'll wait instead of serving the old one.
+  // "invalid" is short for "bundle invalidated", it doesn't imply any errors.
+  compiler.hooks.invalid.tap('invalid', () => {
+    if (isInteractive) {
+      clearConsole();
+    }
+    console.log('Compiling...');
+  });
+
+  let isFirstCompile = true;
+  let tsMessagesPromise;
+
+  if (useTypeScript) {
+    forkTsCheckerWebpackPlugin
+      .getCompilerHooks(compiler)
+      .waiting.tap('awaitingTypeScriptCheck', () => {
+        console.log(
+          chalk.yellow(
+            'Files successfully emitted, waiting for typecheck results...'
+          )
+        );
+      });
+  }
+
+  // "done" event fires when webpack has finished recompiling the bundle.
+  // Whether or not you have warnings or errors, you will get this event.
+  compiler.hooks.done.tap('done', async stats => {
+    if (isInteractive) {
+      clearConsole();
+    }
+
+    // We have switched off the default webpack output in WebpackDevServer
+    // options so we are going to "massage" the warnings and errors and present
+    // them in a readable focused way.
+    // We only construct the warnings and errors for speed:
+    // https://github.com/facebook/create-react-app/issues/4492#issuecomment-421959548
+    const statsData = stats.toJson({
+      all: false,
+      warnings: true,
+      errors: true,
+    });
+
+    const messages = formatWebpackMessages(statsData);
+    const isSuccessful = !messages.errors.length && !messages.warnings.length;
+    if (isSuccessful) {
+      console.log(chalk.green('Compiled successfully!'));
+    }
+    if (isSuccessful && (isInteractive || isFirstCompile)) {
+      printInstructions(appName, urls, useYarn);
+    }
+    isFirstCompile = false;
+
+    // If errors exist, only show errors.
+    if (messages.errors.length) {
+      // Only keep the first error. Others are often indicative
+      // of the same problem, but confuse the reader with noise.
+      if (messages.errors.length > 1) {
+        messages.errors.length = 1;
+      }
+      console.log(chalk.red('Failed to compile.\n'));
+      console.log(messages.errors.join('\n\n'));
+      return;
+    }
+
+    // Show warnings if no errors were found.
+    if (messages.warnings.length) {
+      console.log(chalk.yellow('Compiled with warnings.\n'));
+      console.log(messages.warnings.join('\n\n'));
+
+      // Teach some ESLint tricks.
+      console.log(
+        '\nSearch for the ' +
+          chalk.underline(chalk.yellow('keywords')) +
+          ' to learn more about each warning.'
+      );
+      console.log(
+        'To ignore, add ' +
+          chalk.cyan('// eslint-disable-next-line') +
+          ' to the line before.\n'
+      );
+    }
+  });
+
+  // You can safely remove this after ejecting.
+  // We only use this block for testing of Create React App itself:
+  const isSmokeTest = process.argv.some(
+    arg => arg.indexOf('--smoke-test') > -1
+  );
+  if (isSmokeTest) {
+    compiler.hooks.failed.tap('smokeTest', async () => {
+      await tsMessagesPromise;
+      process.exit(1);
+    });
+    compiler.hooks.done.tap('smokeTest', async stats => {
+      await tsMessagesPromise;
+      if (stats.hasErrors() || stats.hasWarnings()) {
+        process.exit(1);
+      } else {
+        process.exit(0);
+      }
+    });
+  }
+
+  return compiler;
+}
+
+function resolveLoopback(proxy) {
+  const o = url.parse(proxy);
+  o.host = undefined;
+  if (o.hostname !== 'localhost') {
+    return proxy;
+  }
+  // Unfortunately, many languages (unlike node) do not yet support IPv6.
+  // This means even though localhost resolves to ::1, the application
+  // must fall back to IPv4 (on 127.0.0.1).
+  // We can re-enable this in a few years.
+  /*try {
+    o.hostname = address.ipv6() ? '::1' : '127.0.0.1';
+  } catch (_ignored) {
+    o.hostname = '127.0.0.1';
+  }*/
+
+  try {
+    // Check if we're on a network; if we are, chances are we can resolve
+    // localhost. Otherwise, we can just be safe and assume localhost is
+    // IPv4 for maximum compatibility.
+    if (!address.ip()) {
+      o.hostname = '127.0.0.1';
+    }
+  } catch (_ignored) {
+    o.hostname = '127.0.0.1';
+  }
+  return url.format(o);
+}
+
+// We need to provide a custom onError function for httpProxyMiddleware.
+// It allows us to log custom error messages on the console.
+function onProxyError(proxy) {
+  return (err, req, res) => {
+    const host = req.headers && req.headers.host;
+    console.log(
+      chalk.red('Proxy error:') +
+        ' Could not proxy request ' +
+        chalk.cyan(req.url) +
+        ' from ' +
+        chalk.cyan(host) +
+        ' to ' +
+        chalk.cyan(proxy) +
+        '.'
+    );
+    console.log(
+      'See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (' +
+        chalk.cyan(err.code) +
+        ').'
+    );
+    console.log();
+
+    // And immediately send the proper error response to the client.
+    // Otherwise, the request will eventually timeout with ERR_EMPTY_RESPONSE on the client side.
+    if (res.writeHead && !res.headersSent) {
+      res.writeHead(500);
+    }
+    res.end(
+      'Proxy error: Could not proxy request ' +
+        req.url +
+        ' from ' +
+        host +
+        ' to ' +
+        proxy +
+        ' (' +
+        err.code +
+        ').'
+    );
+  };
+}
+
+function prepareProxy(proxy, appPublicFolder, servedPathname) {
+  // `proxy` lets you specify alternate servers for specific requests.
+  if (!proxy) {
+    return undefined;
+  }
+  if (typeof proxy !== 'string') {
+    console.log(
+      chalk.red('When specified, "proxy" in package.json must be a string.')
+    );
+    console.log(
+      chalk.red('Instead, the type of "proxy" was "' + typeof proxy + '".')
+    );
+    console.log(
+      chalk.red('Either remove "proxy" from package.json, or make it a string.')
+    );
+    process.exit(1);
+  }
+
+  // If proxy is specified, let it handle any request except for
+  // files in the public folder and requests to the WebpackDevServer socket endpoint.
+  // https://github.com/facebook/create-react-app/issues/6720
+  const sockPath = process.env.WDS_SOCKET_PATH || '/ws';
+  const isDefaultSockHost = !process.env.WDS_SOCKET_HOST;
+  function mayProxy(pathname) {
+    const maybePublicPath = path.resolve(
+      appPublicFolder,
+      pathname.replace(new RegExp('^' + servedPathname), '')
+    );
+    const isPublicFileRequest = fs.existsSync(maybePublicPath);
+    // used by webpackHotDevClient
+    const isWdsEndpointRequest =
+      isDefaultSockHost && pathname.startsWith(sockPath);
+    return !(isPublicFileRequest || isWdsEndpointRequest);
+  }
+
+  if (!/^http(s)?:\/\//.test(proxy)) {
+    console.log(
+      chalk.red(
+        'When "proxy" is specified in package.json it must start with either http:// or https://'
+      )
+    );
+    process.exit(1);
+  }
+
+  let target;
+  if (process.platform === 'win32') {
+    target = resolveLoopback(proxy);
+  } else {
+    target = proxy;
+  }
+  return [
+    {
+      target,
+      logLevel: 'silent',
+      // For single page apps, we generally want to fallback to /index.html.
+      // However we also want to respect `proxy` for API calls.
+      // So if `proxy` is specified as a string, we need to decide which fallback to use.
+      // We use a heuristic: We want to proxy all the requests that are not meant
+      // for static assets and as all the requests for static assets will be using
+      // `GET` method, we can proxy all non-`GET` requests.
+      // For `GET` requests, if request `accept`s text/html, we pick /index.html.
+      // Modern browsers include text/html into `accept` header when navigating.
+      // However API calls like `fetch()` won’t generally accept text/html.
+      // If this heuristic doesn’t work well for you, use `src/setupProxy.js`.
+      context: function (pathname, req) {
+        return (
+          req.method !== 'GET' ||
+          (mayProxy(pathname) &&
+            req.headers.accept &&
+            req.headers.accept.indexOf('text/html') === -1)
+        );
+      },
+      onProxyReq: proxyReq => {
+        // Browsers may send Origin headers even with same-origin
+        // requests. To prevent CORS issues, we have to change
+        // the Origin to match the target URL.
+        if (proxyReq.getHeader('origin')) {
+          proxyReq.setHeader('origin', target);
+        }
+      },
+      onError: onProxyError(target),
+      secure: false,
+      changeOrigin: true,
+      ws: true,
+      xfwd: true,
+    },
+  ];
+}
+
+function choosePort(host, defaultPort) {
+  return detect(defaultPort, host).then(
+    port =>
+      new Promise(resolve => {
+        if (port === defaultPort) {
+          return resolve(port);
+        }
+        const message =
+          process.platform !== 'win32' && defaultPort < 1024 && !isRoot()
+            ? `Admin permissions are required to run a server on a port below 1024.`
+            : `Something is already running on port ${defaultPort}.`;
+        if (isInteractive) {
+          clearConsole();
+          const existingProcess = getProcessForPort(defaultPort);
+          const question = {
+            type: 'confirm',
+            name: 'shouldChangePort',
+            message:
+              chalk.yellow(
+                message +
+                  `${existingProcess ? ` Probably:\n  ${existingProcess}` : ''}`
+              ) + '\n\nWould you like to run the app on another port instead?',
+            initial: true,
+          };
+          prompts(question).then(answer => {
+            if (answer.shouldChangePort) {
+              resolve(port);
+            } else {
+              resolve(null);
+            }
+          });
+        } else {
+          console.log(chalk.red(message));
+          resolve(null);
+        }
+      }),
+    err => {
+      throw new Error(
+        chalk.red(`Could not find an open port at ${chalk.bold(host)}.`) +
+          '\n' +
+          ('Network error message: ' + err.message || err) +
+          '\n'
+      );
+    }
+  );
+}
+
+module.exports = {
+  choosePort,
+  createCompiler,
+  prepareProxy,
+  prepareUrls,
+};