diff --git a/.eslintrc.yml b/.eslintrc.yml
index e3bfeab87..401c6cd4f 100644
--- a/.eslintrc.yml
+++ b/.eslintrc.yml
@@ -24,9 +24,18 @@ rules:
   prefer-arrow-callback: error
   prefer-const: error
   react/no-deprecated: off
+  react/prop-types: off
   strict: error
   symbol-description: error
   yoda:
   - error
   - never
   - exceptRange: true
+overrides:
+  - files:
+    - website/playground/**
+    env:
+      es6: true
+      browser: true
+    parserOptions:
+      sourceType: module
diff --git a/website/playground/Playground.js b/website/playground/Playground.js
index 3c0ef6d04..ea86b93d3 100644
--- a/website/playground/Playground.js
+++ b/website/playground/Playground.js
@@ -10,7 +10,6 @@ import formatMarkdown from "./markdown";
 
 import { Sidebar, SidebarCategory } from "./sidebar/components";
 import SidebarOptions from "./sidebar/SidebarOptions";
-import Option from "./sidebar/options";
 import { Checkbox } from "./sidebar/inputs";
 
 const CATEGORIES_ORDER = ["Global", "JavaScript", "Markdown", "Special"];
@@ -68,14 +67,14 @@ class Playground extends React.Component {
   }
 
   render() {
-    const { availableOptions } = this.props;
+    const { availableOptions, worker } = this.props;
     const { content, options } = this.state;
 
     return (
       <EditorState>
         {editorState => (
           <PrettierFormat
-            worker={this.props.worker}
+            worker={worker}
             code={content}
             options={options}
             debugAst={editorState.showAst}
@@ -150,7 +149,7 @@ class Playground extends React.Component {
                     <Button onClick={this.clearContent}>Clear</Button>
                   </div>
                   <div className="bottom-bar-buttons bottom-bar-buttons-right">
-                    <ClipboardButton copy={() => window.location.href}>
+                    <ClipboardButton copy={window.location.href}>
                       Copy link
                     </ClipboardButton>
                     <ClipboardButton
@@ -188,7 +187,7 @@ function getCliOptions(availableOptions, options) {
   const cliOptions = [];
   for (let i = 0; i < availableOptions.length; i++) {
     const option = availableOptions[i];
-    let value = options[option.name];
+    const value = options[option.name];
 
     if (option.type === "boolean") {
       if ((value && !option.inverted) || (!value && option.inverted)) {
diff --git a/website/playground/PrettierFormat.js b/website/playground/PrettierFormat.js
index 46113c6da..a1c895de7 100644
--- a/website/playground/PrettierFormat.js
+++ b/website/playground/PrettierFormat.js
@@ -7,7 +7,7 @@ function getFormatProps(props) {
   return { code, options, debugAst, debugDoc, secondFormat };
 }
 
-export default class extends React.Component {
+export default class PrettierFormat extends React.Component {
   constructor() {
     super();
     this.state = { formatted: "" };
diff --git a/website/playground/WorkerApi.js b/website/playground/WorkerApi.js
index 02e75f43e..cc580090e 100644
--- a/website/playground/WorkerApi.js
+++ b/website/playground/WorkerApi.js
@@ -1,12 +1,14 @@
 export default function(source) {
   const worker = new Worker(source);
   let counter = 0;
-  let handlers = {};
+  const handlers = {};
 
   worker.addEventListener("message", event => {
     const { uid, message, error } = event.data;
 
-    if (!handlers[uid]) return;
+    if (!handlers[uid]) {
+      return;
+    }
 
     const [resolve, reject] = handlers[uid];
     delete handlers[uid];
diff --git a/website/playground/buttons.js b/website/playground/buttons.js
index cc51ecd02..32c7081c0 100644
--- a/website/playground/buttons.js
+++ b/website/playground/buttons.js
@@ -30,7 +30,9 @@ export class ClipboardButton extends React.Component {
 
   showTooltip(text) {
     this.setState({ showTooltip: true, tooltipText: text }, () => {
-      if (this.timer) clearTimeout(this.timer);
+      if (this.timer) {
+        clearTimeout(this.timer);
+      }
       this.timer = setTimeout(() => {
         this.timer = null;
         this.setState({ showTooltip: false });
diff --git a/website/playground/helpers.js b/website/playground/helpers.js
index f36930bb3..d54395b8d 100644
--- a/website/playground/helpers.js
+++ b/website/playground/helpers.js
@@ -1,5 +1,5 @@
 export function stateToggler(key) {
-  return state => ({ [key]: !Boolean(state[key]) });
+  return state => ({ [key]: !state[key] });
 }
 
 const hasOwnProperty = Object.prototype.hasOwnProperty;
@@ -10,14 +10,15 @@ function is(x, y) {
     // Steps 1-5, 7-10
     // Steps 6.b-6.e: +0 != -0
     return x !== 0 || 1 / x === 1 / y;
-  } else {
-    // Step 6.a: NaN == NaN
-    return x !== x && y !== y;
   }
+  // Step 6.a: NaN == NaN
+  return x !== x && y !== y;
 }
 
 export function shallowEqual(objA, objB) {
-  if (is(objA, objB)) return true;
+  if (is(objA, objB)) {
+    return true;
+  }
 
   if (
     typeof objA !== "object" ||
@@ -31,7 +32,9 @@ export function shallowEqual(objA, objB) {
   const keysA = Object.keys(objA);
   const keysB = Object.keys(objB);
 
-  if (keysA.length !== keysB.length) return false;
+  if (keysA.length !== keysB.length) {
+    return false;
+  }
 
   for (let i = 0; i < keysA.length; i++) {
     if (
diff --git a/website/playground/index.js b/website/playground/index.js
index 871f387c4..b2419bbf8 100644
--- a/website/playground/index.js
+++ b/website/playground/index.js
@@ -45,7 +45,9 @@ class App extends React.Component {
   render() {
     const { loaded, availableOptions, version } = this.state;
 
-    if (!loaded) return "Loading...";
+    if (!loaded) {
+      return "Loading...";
+    }
 
     return (
       <React.Fragment>
@@ -69,7 +71,9 @@ function parsePrettierOptions(supportInfo) {
   }, {});
 
   return ENABLED_OPTIONS.reduce((optionsList, optionConfig) => {
-    if (!supportedOptions[optionConfig.name]) return optionsList;
+    if (!supportedOptions[optionConfig.name]) {
+      return optionsList;
+    }
 
     const option = Object.assign(
       {},
diff --git a/website/playground/markdown.js b/website/playground/markdown.js
index 366aff9a6..f67b0be30 100644
--- a/website/playground/markdown.js
+++ b/website/playground/markdown.js
@@ -55,13 +55,13 @@ function formatCLIOptions(cliOptions) {
 }
 
 function codeBlock(content, syntax) {
-  var backtickSequences = content.match(/`+/g) || [];
-  var longestBacktickSequenceLength = Math.max.apply(
+  const backtickSequences = content.match(/`+/g) || [];
+  const longestBacktickSequenceLength = Math.max.apply(
     null,
     backtickSequences.map(backticks => backticks.length)
   );
-  var fenceLength = Math.max(3, longestBacktickSequenceLength + 1);
-  var fence = Array(fenceLength + 1).join("`");
+  const fenceLength = Math.max(3, longestBacktickSequenceLength + 1);
+  const fence = Array(fenceLength + 1).join("`");
   return [fence + (syntax || ""), content, fence].join("\n");
 }