a few changes to make A/B testing easier

server/routes/jsconfig.js

@@ -0,0 +1,46 @@
+const config = require('../config');
+
+let sentry = '';
+if (config.sentry_id) {
+  //eslint-disable-next-line node/no-missing-require
+  const version = require('../../dist/version.json');
+  sentry = `
+var RAVEN_CONFIG = {
+  release: '${version.version}',
+  tags: {
+    commit: '${version.commit}'
+  },
+  dataCallback: function (data) {
+    var hash = window.location.hash;
+    if (hash) {
+      return JSON.parse(JSON.stringify(data).replace(new RegExp(hash.slice(1), 'g'), ''));
+    }
+    return data;
+  }
+}
+var SENTRY_ID = '${config.sentry_id}';
+`;
+}
+
+let ga = '';
+if (config.analytics_id) {
+  ga = `var GOOGLE_ANALYTICS_ID = ${config.analytics_id};`;
+}
+
+/* eslint-disable no-useless-escape */
+const jsconfig = `
+var isIE = /trident\\\/7\.|msie/i.test(navigator.userAgent);
+var isUnsupportedPage = /\\\/unsupported/.test(location.pathname);
+if (isIE && !isUnsupportedPage) {
+  window.location.replace('/unsupported/ie');
+}
+var MAXFILESIZE = ${config.max_file_size};
+var EXPIRE_SECONDS = ${config.expire_seconds};
+${ga}
+${sentry}
+`;
+
+module.exports = function(req, res) {
+  res.set('Content-Type', 'application/javascript');
+  res.send(jsconfig);
+};