--- a/.eslintignore
+++ b/.eslintignore
@@ -63,17 +63,16 @@ browser/base/content/sanitizeDialog.js
 browser/base/content/test/general/file_csp_block_all_mixedcontent.html
 browser/base/content/test/urlbar/file_blank_but_not_blank.html
 browser/base/content/newtab/**
 browser/components/downloads/**
 browser/components/feeds/**
 browser/components/privatebrowsing/**
 browser/components/sessionstore/**
 browser/components/tabview/**
-browser/components/translation/**
 # generated files in cld2
 browser/components/translation/cld2/cld-worker.js
 browser/extensions/pdfjs/**
 # generated or library files in pocket
 browser/extensions/pocket/content/panels/js/tmpl.js
 browser/extensions/pocket/content/panels/js/vendor/**
 browser/locales/**
 

--- a/browser/components/translation/BingTranslator.jsm
+++ b/browser/components/translation/BingTranslator.jsm
@@ -281,17 +281,17 @@ function BingRequest(translationData, so
   this.characterCount = 0;
 }
 
 BingRequest.prototype = {
   /**
    * Initiates the request
    */
   fireRequest: function() {
-    return Task.spawn(function *(){
+    return Task.spawn(function *() {
       // Prepare authentication.
       let token = yield BingTokenManager.getToken();
       let auth = "Bearer " + token;
 
       // Prepare URL.
       let url = getUrlParam("https://api.microsofttranslator.com/v2/Http.svc/TranslateArray",
                             "browser.translation.bing.translateArrayURL");
 

--- a/browser/components/translation/TranslationDocument.jsm
+++ b/browser/components/translation/TranslationDocument.jsm
@@ -161,29 +161,27 @@ this.TranslationDocument.prototype = {
         // it's a translation node: it has useful content for translation.
         // In this case, we need to stringify this node.
         // However, if this item is a root, we should skip it here in this
         // object's child list (and just add a placeholder for it), because
         // it will be stringfied separately for being a root.
         item.original.push(objInMap);
         str += this.generateTextForItem(objInMap);
         wasLastItemPlaceholder = false;
-      } else {
+      } else if (!wasLastItemPlaceholder) {
         // Otherwise, if this node doesn't contain any useful content,
         // or if it is a root itself, we can replace it with a placeholder node.
         // We can't simply eliminate this node from our string representation
         // because that could change the HTML structure (e.g., it would
         // probably merge two separate text nodes).
         // It's not necessary to add more than one placeholder in sequence;
         // we can optimize them away.
-        if (!wasLastItemPlaceholder) {
-          item.original.push(TranslationItem_NodePlaceholder);
-          str += '<br>';
-          wasLastItemPlaceholder = true;
-        }
+        item.original.push(TranslationItem_NodePlaceholder);
+        str += '<br>';
+        wasLastItemPlaceholder = true;
       }
     }
 
     return generateTranslationHtmlForItem(item, str);
   },
 
   /**
    * Changes the document to display its translated
@@ -272,19 +270,25 @@ function TranslationItem(node, id, isRoo
   this.children = [];
 }
 
 TranslationItem.prototype = {
   isRoot: false,
   isSimpleRoot: false,
 
   toString: function() {
-    let rootType = this.isRoot
-                   ? (this.isSimpleRoot ? ' (simple root)' : ' (non simple root)')
-                   : '';
+    let rootType = "";
+    if (this.isRoot) {
+      if (this.isSimpleRoot) {
+        rootType = " (simple root)";
+      }
+      else {
+        rootType = " (non simple root)";
+      }
+    }
     return "[object TranslationItem: <" + this.nodeRef.localName + ">"
            + rootType + "]";
   },
 
   /**
    * This function will parse the result of the translation of one translation
    * item. If this item was a simple root, all we sent was a plain-text version
    * of it, so the result is also straightforward text.

--- a/browser/components/translation/YandexTranslator.jsm
+++ b/browser/components/translation/YandexTranslator.jsm
@@ -288,17 +288,17 @@ function YandexRequest(translationData, 
   this.characterCount = 0;
 }
 
 YandexRequest.prototype = {
   /**
    * Initiates the request
    */
   fireRequest: function() {
-    return Task.spawn(function *(){
+    return Task.spawn(function *() {
       // Prepare URL.
       let url = getUrlParam("https://translate.yandex.net/api/v1.5/tr.json/translate",
                             "browser.translation.yandex.translateURLOverride");
 
       // Prepare the request body.
       let apiKey = getUrlParam("%YANDEX_API_KEY%", "browser.translation.yandex.apiKeyOverride");
       let params = [
         ["key", apiKey],

--- a/browser/components/translation/cld2/post.js
+++ b/browser/components/translation/cld2/post.js
@@ -120,17 +120,17 @@ var Encodings = {
 // Accept forms both with and without underscores/hypens.
 for (let code of Object.keys(Encodings)) {
   if (code['includes']("_"))
     Encodings[code.replace(/_/g, "")] = Encodings[code];
 }
 
 addOnPreMain(function() {
 
-  onmessage = function(aMsg){
+  onmessage = function(aMsg) {
     let data = aMsg['data'];
 
     let langInfo;
     if (data['tld'] == undefined && data['encoding'] == undefined && data['language'] == undefined) {
       langInfo = LanguageInfo.detectLanguage(data['text'], !data['isHTML']);
     } else {
       // Do our best to find the given encoding in the encodings table.
       // Otherwise, just fall back to unknown.

--- a/browser/components/translation/test/browser_translation_bing.js
+++ b/browser/components/translation/test/browser_translation_bing.js
@@ -98,17 +98,17 @@ add_task(function* test_handling_out_of_
 });
 
 /**
  * A helper function for constructing a URL to a page stored in the
  * local fixture folder.
  *
  * @param filename  Name of a fixture file.
  */
-function constructFixtureURL(filename){
+function constructFixtureURL(filename) {
   // Deduce the Mochitest server address in use from a pref that was pre-processed.
   let server = Services.prefs.getCharPref("browser.translation.bing.authURL")
                              .replace("http://", "");
   server = server.substr(0, server.indexOf("/"));
   let url = "http://" + server +
     "/browser/browser/components/translation/test/fixtures/" + filename;
   return url;
 }

--- a/browser/components/translation/test/browser_translation_telemetry.js
+++ b/browser/components/translation/test/browser_translation_telemetry.js
@@ -19,17 +19,17 @@ var MetricsChecker = {
     AUTO_REJECTED         : Services.telemetry.getHistogramById("AUTO_REJECTED_TRANSLATION_OFFERS"),
     SHOW_ORIGINAL         : Services.telemetry.getHistogramById("REQUESTS_OF_ORIGINAL_CONTENT"),
     TARGET_CHANGES        : Services.telemetry.getHistogramById("CHANGES_OF_TARGET_LANGUAGE"),
     DETECTION_CHANGES     : Services.telemetry.getHistogramById("CHANGES_OF_DETECTED_LANGUAGE"),
     SHOW_UI               : Services.telemetry.getHistogramById("SHOULD_TRANSLATION_UI_APPEAR"),
     DETECT_LANG           : Services.telemetry.getHistogramById("SHOULD_AUTO_DETECT_LANGUAGE"),
   },
 
-  reset: function(){
+  reset: function() {
     for (let i of Object.keys(this.HISTOGRAMS)) {
       this.HISTOGRAMS[i].clear();
     }
     this.updateMetrics();
   },
 
   updateMetrics: function () {
     this._metrics = {
@@ -60,17 +60,17 @@ var MetricsChecker = {
         this._metrics.pageCountByLang[key] = pages[key] ? pages[key].sum : 0;
       }
     }
   },
 
   /**
    * A recurrent loop for making assertions about collected metrics.
    */
-  _assertionLoop: function (prevMetrics, metrics, additions){
+  _assertionLoop: function (prevMetrics, metrics, additions) {
     for (let metric of Object.keys(additions)) {
       let addition = additions[metric];
       // Allows nesting metrics. Useful for keyed histograms.
       if (typeof addition === 'object') {
         this._assertionLoop(prevMetrics[metric], metrics[metric], addition);
         continue;
       }
       Assert.equal(prevMetrics[metric] + addition, metrics[metric]);
@@ -112,19 +112,19 @@ var acceptTranslationOffer = Task.async(
   yield waitForMessage(browser, "Translation:Finished");
 });
 
 var translate = Task.async(function*(text, from, closeTab = true) {
   let tab = yield offerTranslationFor(text, from);
   yield acceptTranslationOffer(tab);
   if (closeTab) {
     gBrowser.removeTab(tab);
-  } else {
-    return tab;
+    return null;
   }
+  return tab;
 });
 
 function waitForMessage({messageManager}, name) {
   return new Promise(resolve => {
     messageManager.addMessageListener(name, function onMessage() {
       messageManager.removeMessageListener(name, onMessage);
       resolve();
     });

--- a/browser/components/translation/test/browser_translation_yandex.js
+++ b/browser/components/translation/test/browser_translation_yandex.js
@@ -86,17 +86,17 @@ add_task(function* test_preference_attri
 });
 
 /**
  * A helper function for constructing a URL to a page stored in the
  * local fixture folder.
  *
  * @param filename  Name of a fixture file.
  */
-function constructFixtureURL(filename){
+function constructFixtureURL(filename) {
   // Deduce the Mochitest server address in use from a pref that was pre-processed.
   let server = Services.prefs.getCharPref("browser.translation.yandex.translateURLOverride")
                              .replace("http://", "");
   server = server.substr(0, server.indexOf("/"));
   let url = "http://" + server +
     "/browser/browser/components/translation/test/fixtures/" + filename;
   return url;
 }