Adding prettierrc with some initial rules

.prettierrc

@@ -0,0 +1,6 @@
+{
+  "trailingComma": "es5",
+  "tabWidth": 2,
+  "semi": true,
+  "singleQuote": true
+}

_data/topics.json

@@ -1,7 +1,7 @@
 [
   {
-    "title": "Buffer and Streams",
-    "url": "/buffer-and-streams/"
+    "title": "Buffers and Streams",
+    "url": "/buffers-and-streams/"
   },
   {
     "title": "Control flow",

events/index.md

@@ -17,22 +17,22 @@ When the EventEmitter object emits an event, all of the functions attached to th
 This example creates an event listener for `foo` events, and an event emitter to fire these events.
 
 ```javascript
-const { EventEmitter } = require("events");
+const { EventEmitter } = require('events');
 
 // create a listener function. These can be arrow functions, but will
 // loose `this` refering to the EventEmitter object
 const foo = function foo() {
-  console.log("foo executed.", this);
+  console.log('foo executed.', this);
 };
 
 // create an emitter and bind some events to it
 const eventEmitter = new EventEmitter();
 
 // Bind the connection event with the listner1 function
-eventEmitter.on("foo", foo);
+eventEmitter.on('foo', foo);
 
 // fire the event
-eventEmitter.emit("foo");
+eventEmitter.emit('foo');
 ```
 
 ## Passing parameters

js/main.js

@@ -1,4 +1,4 @@
-window.addEventListener("DOMContentLoaded", event => {
+window.addEventListener('DOMContentLoaded', event => {
   if (window.localStorage) {
     window.topicsCompleted = getTopicsFromLocalStorage();
     updateUI();
@@ -22,7 +22,7 @@ function checkForCompletedButtons() {
 }
 
 function getButtons() {
-  return document.querySelectorAll(".completed-button");
+  return document.querySelectorAll('.completed-button');
 }
 
 function toggleCompletedTopic(topic) {
@@ -40,17 +40,17 @@ function isCompleted(topic) {
 }
 
 function markButtonAsCompleted(button) {
-  button.classList.add("completed");
-  button.innerText = "Completed!";
+  button.classList.add('completed');
+  button.innerText = 'Completed!';
 }
 
 function markButtonAsNotCompleted(button) {
-  button.classList.remove("completed");
-  button.innerText = "Mark as completed";
+  button.classList.remove('completed');
+  button.innerText = 'Mark as completed';
 }
 
 function getTopicsFromLocalStorage() {
-  return JSON.parse(window.localStorage.getItem("topicsCompleted"));
+  return JSON.parse(window.localStorage.getItem('topicsCompleted'));
 }
 
 function addCompletedTopic(topic) {
@@ -64,7 +64,7 @@ function addCompletedTopic(topic) {
 
 function save(topics) {
   window.topicsCompleted = topics;
-  window.localStorage.setItem("topicsCompleted", JSON.stringify(topics));
+  window.localStorage.setItem('topicsCompleted', JSON.stringify(topics));
 }
 
 function removeCompletedTopic(topic) {
@@ -73,16 +73,16 @@ function removeCompletedTopic(topic) {
 }
 
 function getSidebarItems() {
-  return document.querySelectorAll(".topics li");
+  return document.querySelectorAll('.topics li');
 }
 
 function checkSideBar() {
   [...getSidebarItems()].forEach(item => {
     const topic = item.dataset.topic;
     if (isCompleted(topic)) {
-      item.classList.add("completed");
+      item.classList.add('completed');
     } else {
-      item.classList.remove("completed");
+      item.classList.remove('completed');
     }
   });
 }

styleguide/index.md

@@ -114,7 +114,7 @@ A paragraph (from the Greek paragraphos, “to write beside” or “written bes
 
 ```javascript
 function whereTo() {
-  const foo = "bar";
+  const foo = 'bar';
   for (let i = 0; i < 10; i++) {
     console.log(foo);
   }