diff --git a/src/components/Icon.js b/src/components/Icon.js
index 3d23dd9..1723529 100644
--- a/src/components/Icon.js
+++ b/src/components/Icon.js
@@ -69,10 +69,12 @@ function getSVGIconComponent(type) {
   }
 }
 
+const iconStyle = { width: '100%', height: '100%' }
+
 export default function Icon({ type, className, ...otherProps }) {
   return (
     <div className={cx('octicon-wrapper', className)} {...otherProps}>
-      {React.createElement(getSVGIconComponent(type), { width: '100%', height: '100%' })}
+      {React.createElement(getSVGIconComponent(type), iconStyle)}
     </div>
   )
 }
diff --git a/src/components/Node.js b/src/components/Node.js
index 49f6ae8..7f65cec 100644
--- a/src/components/Node.js
+++ b/src/components/Node.js
@@ -1,10 +1,8 @@
 import React from 'react'
-import PJAX from 'pjax'
 
 import Icon from './Icon'
 
 import cx from '../utils/cx'
-import general from '../utils/general'
 import DOMHelper from '../utils/DOMHelper'
 
 function getIconType(node) {
@@ -31,7 +29,7 @@ export default class Node extends React.PureComponent {
   }
 
   render() {
-    const { node, depth, expanded, focused, pjax } = this.props
+    const { node, depth, expanded, focused } = this.props
     const { name, path } = node
     return (
       <div className={cx(`node-item-row`, { focused })} title={path}>
diff --git a/src/components/ResizeHandler.js b/src/components/ResizeHandler.js
index 4fac68d..2599e81 100644
--- a/src/components/ResizeHandler.js
+++ b/src/components/ResizeHandler.js
@@ -2,7 +2,7 @@ import React from 'react'
 
 import Icon from './Icon'
 
-export default class ResizeHandler extends React.Component {
+export default class ResizeHandler extends React.PureComponent {
   pointerDown = false
   startX = 0
   delta = 0
diff --git a/src/components/SettingsBar.js b/src/components/SettingsBar.js
index 9c41f00..c4b08bc 100644
--- a/src/components/SettingsBar.js
+++ b/src/components/SettingsBar.js
@@ -37,7 +37,7 @@ function friendlyFormatShortcut(shortcut) {
   }
 }
 
-export default class SettingsBar extends React.Component {
+export default class SettingsBar extends React.PureComponent {
   state = {
     accessTokenHint: null,
     accessToken: '',
diff --git a/src/utils/URLHelper.js b/src/utils/URLHelper.js
index b5be2a6..07bdfde 100644
--- a/src/utils/URLHelper.js
+++ b/src/utils/URLHelper.js
@@ -35,7 +35,7 @@ const TYPES = {
 }
 function isInCodePage(metaData = {}) {
   const { userName, repoName, type, branchName } = { ...parseRaw(), ...metaData }
-  return (
+  return Boolean(
     userName &&
     !RESERVED_NAME.find(_ => _ === userName) &&
     repoName &&
diff --git a/src/utils/treeParser.js b/src/utils/treeParser.js
index 7a6c6a1..37f75ee 100644
--- a/src/utils/treeParser.js
+++ b/src/utils/treeParser.js
@@ -12,15 +12,15 @@ const nodeTemplate = {
 function sortFoldersToFront(root) {
   const isFolder = node => node.type === 'tree'
   const isNotFolder = (...args) => !isFolder(...args)
-  function DFS(root) {
+  function depthFirstSearch(root) {
     const nodes = root.contents
     if (nodes) {
       nodes.splice(0, Infinity, ...nodes.filter(isFolder), ...nodes.filter(isNotFolder))
-      nodes.forEach(DFS)
+      nodes.forEach(depthFirstSearch)
     }
     return root
   }
-  return DFS(root)
+  return depthFirstSearch(root)
 }
 
 function setParentNode(root, parent = null) {