Fixes some lint issues (#3786)

Fixes lint issues in /home/yash/GitHub/dev.to/app/assets/javascripts/utilities/
	- browserStoreCache.js
	- checkUserLoggedIn.js
	- createAjaxReq.js
	- getCurrentPage.js
	- getImageForLink.js
	- insertAfter.js
	- localDateTime.js
	- localStorageTest.js
	- preventDefaultAction.js

Signed-off-by: Amorpheuz <mail2ypd@gmail.com>

app/assets/javascripts/utilities/browserStoreCache.js

@@ -1,3 +1,5 @@
+'use strict';
+
 function browserStoreCache(action, userData) {
   try {
     switch (action) {
@@ -19,4 +21,5 @@ function browserStoreCache(action, userData) {
       browserStoreCache('remove');
     }
   }
+  return undefined;
 }

app/assets/javascripts/utilities/checkUserLoggedIn.js

@@ -1,3 +1,5 @@
+'use strict';
+
 function checkUserLoggedIn() {
   const body = document.getElementsByTagName('body')[0];
   if (!body) {

app/assets/javascripts/utilities/createAjaxReq.js

@@ -1,7 +1,8 @@
+'use strict';
+
 function createAjaxReq() {
   if (window.XMLHttpRequest) {
     return new XMLHttpRequest();
-  } else {
-    return new ActiveXObject("Microsoft.XMLHTTP");
   }
+  return new window.ActiveXObject('Microsoft.XMLHTTP');
 }

app/assets/javascripts/utilities/getCurrentPage.js

@@ -1,3 +1,8 @@
+'use strict';
+
 function getCurrentPage(classString) {
-    return document.querySelectorAll("[data-current-page='"+classString+"']").length > 0
-}
+  return (
+    document.querySelectorAll("[data-current-page='" + classString + "']")
+      .length > 0
+  );
+}

app/assets/javascripts/utilities/getImageForLink.js

@@ -1,7 +1,9 @@
+'use strict';
+
 var $fetchedImageUrls = [];
-function getImageForLink(elem){
-  var imageUrl = elem.getAttribute('data-preload-image')
-  if (imageUrl && $fetchedImageUrls.indexOf(imageUrl) == -1) {
+function getImageForLink(elem) {
+  var imageUrl = elem.getAttribute('data-preload-image');
+  if (imageUrl && $fetchedImageUrls.indexOf(imageUrl) === -1) {
     var img = new Image();
     img.src = imageUrl;
     $fetchedImageUrls.push(imageUrl);

app/assets/javascripts/utilities/insertAfter.js

@@ -1,5 +1,7 @@
+'use strict';
+
 function insertAfter(newNode, referenceNode) {
-    if (referenceNode && referenceNode.parentNode){
-      referenceNode.parentNode.insertBefore(newNode, referenceNode.nextSibling);
-    }
+  if (referenceNode && referenceNode.parentNode) {
+    referenceNode.parentNode.insertBefore(newNode, referenceNode.nextSibling);
+  }
 }

app/assets/javascripts/utilities/localDateTime.js

@@ -1,3 +1,5 @@
+'use strict';
+
 /* Local date/time utilities */
 
 /*

app/assets/javascripts/utilities/localStorageTest.js

@@ -1,10 +1,12 @@
-function localStorageTest(){
-    var test = 'devtolocalstoragetestforavaialbility';
-    try {
-        localStorage.setItem(test, test);
-        localStorage.removeItem(test);
-        return true;
-    } catch(e) {
-        return false;
-    }
+'use strict';
+
+function localStorageTest() {
+  var test = 'devtolocalstoragetestforavaialbility';
+  try {
+    localStorage.setItem(test, test);
+    localStorage.removeItem(test);
+    return true;
+  } catch (e) {
+    return false;
+  }
 }

app/assets/javascripts/utilities/preventDefaultAction.js

@@ -1,3 +1,5 @@
-function preventDefaultAction(event){
+'use strict';
+
+function preventDefaultAction(event) {
   event.preventDefault();
-}
+}