diff --git a/config.js b/config.js
index b9a6158..d3b74c2 100644
--- a/config.js
+++ b/config.js
@@ -26,6 +26,6 @@ module.exports = {
   lintRoots: ['lib', 'src', 'spec'],
   browserify: {
     debug: true,
-    fullPaths: false,
+    fullPaths: false
   }
 };
diff --git a/gulpfile.js b/gulpfile.js
index a3a0752..6836ca9 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -120,12 +120,11 @@ gulp.task('scripts', function() {
       sourcemaps = require('gulp-sourcemaps'),
       rename = require('gulp-rename');
 
-  var b = browserify(config.browserify)
+  return browserify(config.browserify)
     .transform(require('./lib/canopy-transform'))
     .transform(require('babelify'))
-    .add('./src/js/main.js');
-
-  return b.bundle()
+    .add('./src/js/main.js')
+    .bundle()
     .on('error', notify.onError())
     .pipe(source('./src/js/main.js'))
     .pipe(buffer())
diff --git a/lib/canopy-transform.js b/lib/canopy-transform.js
index f475022..2fe7ef3 100644
--- a/lib/canopy-transform.js
+++ b/lib/canopy-transform.js
@@ -2,12 +2,12 @@ var through = require('through'),
     canopy = require('canopy');
 
 module.exports = function(file) {
+  var data = '';
+
   if (!/\.peg$/.test(file)) {
     return through();
   }
 
-  var data = '';
-
   return through(
     function(buf) {
       data += buf;
diff --git a/spec/parser/javascript/match_spec.js b/spec/parser/javascript/match_spec.js
index a8c8e75..c914288 100644
--- a/spec/parser/javascript/match_spec.js
+++ b/spec/parser/javascript/match_spec.js
@@ -25,7 +25,7 @@ describe('parser/javascript/match.js', function() {
         jasmine.objectContaining({
           content: jasmine.objectContaining({ literal: 'example' })
         })
-      ],
+      ]
     },
     'example$': {
       anchorStart: false,
diff --git a/spec/parser/javascript/node_spec.js b/spec/parser/javascript/node_spec.js
index de378fa..99bdb06 100644
--- a/spec/parser/javascript/node_spec.js
+++ b/spec/parser/javascript/node_spec.js
@@ -30,7 +30,9 @@ describe('parser/javascript/node.js', function() {
       this.node.module = {
         definedProperties: {
           example: {
-            get: function() { return 'value'; }
+            get: function() {
+              return 'value';
+            }
           }
         }
       };
@@ -77,28 +79,28 @@ describe('parser/javascript/node.js', function() {
   describe('#getBBox', function() {
 
     it('returns the normalized bbox of the container merged with the anchor', function() {
-        this.node.proxy = {
-          anchor: {
-            anchor: 'example anchor'
-          }
-        };
-        this.node.container = jasmine.createSpyObj('container', ['addClass', 'getBBox']);
-        this.node.container.getBBox.and.returnValue({
-          bbox: 'example bbox',
-          x: 'left',
-          x2: 'right',
-          cy: 'center'
-        });
-        expect(this.node.getBBox()).toEqual({
-          bbox: 'example bbox',
-          anchor: 'example anchor',
-          x: 'left',
-          x2: 'right',
-          cy: 'center',
-          ax: 'left',
-          ax2: 'right',
-          ay: 'center'
-        });
+      this.node.proxy = {
+        anchor: {
+          anchor: 'example anchor'
+        }
+      };
+      this.node.container = jasmine.createSpyObj('container', ['addClass', 'getBBox']);
+      this.node.container.getBBox.and.returnValue({
+        bbox: 'example bbox',
+        x: 'left',
+        x2: 'right',
+        cy: 'center'
+      });
+      expect(this.node.getBBox()).toEqual({
+        bbox: 'example bbox',
+        anchor: 'example anchor',
+        x: 'left',
+        x2: 'right',
+        cy: 'center',
+        ax: 'left',
+        ax2: 'right',
+        ay: 'center'
+      });
     });
 
   });
diff --git a/spec/parser/javascript_spec.js b/spec/parser/javascript_spec.js
index ce18a7b..b7a43aa 100644
--- a/spec/parser/javascript_spec.js
+++ b/spec/parser/javascript_spec.js
@@ -123,7 +123,7 @@ describe('parser/javascript.js', function() {
       it('sets the dimensions of the image', function(done) {
         this.parser.render()
           .then(() => {
-            var svg = this.container.querySelector('svg');
+            let svg = this.container.querySelector('svg');
 
             expect(svg.getAttribute('width')).toEqual('62');
             expect(svg.getAttribute('height')).toEqual('44');
diff --git a/spec/regexper_spec.js b/spec/regexper_spec.js
index 9edbb47..cc4e985 100644
--- a/spec/regexper_spec.js
+++ b/spec/regexper_spec.js
@@ -17,7 +17,7 @@ describe('regexper.js', function() {
       '</form>',
       '<div id="error"></div>',
       '<ul id="warnings"></ul>',
-      '<div id="regexp-render"></div>',
+      '<div id="regexp-render"></div>'
     ].join('');
 
     this.regexper = new Regexper(this.root);
diff --git a/src/js/main.js b/src/js/main.js
index fce746b..b1c8562 100644
--- a/src/js/main.js
+++ b/src/js/main.js
@@ -44,7 +44,7 @@ window._gaq = (typeof _gaq !== 'undefined') ? _gaq : {
   // Initialize the main page of the site. Functionality is kept in the
   // [Regexper class](./regexper.html).
   if (document.body.querySelector('#content .application')) {
-    var regexper = new Regexper(document.body);
+    let regexper = new Regexper(document.body);
 
     regexper.detectBuggyHash();
     regexper.bindListeners();
diff --git a/src/js/parser/javascript.js b/src/js/parser/javascript.js
index 5eb9128..75c5221 100644
--- a/src/js/parser/javascript.js
+++ b/src/js/parser/javascript.js
@@ -84,7 +84,7 @@ export default class Parser {
       // Once rendering is complete, the rendered expression is positioned and
       // the SVG resized to create some padding around the image contents.
       .then(result => {
-        var box = result.getBBox();
+        let box = result.getBBox();
 
         result.transform(Snap.matrix()
           .translate(10 - box.x, 10 - box.y));
diff --git a/src/js/parser/javascript/literal.js b/src/js/parser/javascript/literal.js
index 69a6cb8..e5e841d 100644
--- a/src/js/parser/javascript/literal.js
+++ b/src/js/parser/javascript/literal.js
@@ -10,7 +10,7 @@ export default {
   _render() {
     return this.renderLabel(['\u201c', this.literal, '\u201d'])
       .then(label => {
-        var spans = label.selectAll('tspan');
+        let spans = label.selectAll('tspan');
 
         // The quote marks get some styling to lighten their color so they are
         // distinct from the actual literal value.
diff --git a/src/js/parser/javascript/match_fragment.js b/src/js/parser/javascript/match_fragment.js
index c2e786c..1ae45f8 100644
--- a/src/js/parser/javascript/match_fragment.js
+++ b/src/js/parser/javascript/match_fragment.js
@@ -29,7 +29,7 @@ export default {
   _render() {
     return this.content.render(this.container.group())
       .then(() => {
-        var box, paths;
+        let box, paths;
 
         // Contents must be transformed based on the repeat that is applied.
         this.content.transform(this.repeat.contentPosition);
diff --git a/src/js/parser/javascript/node.js b/src/js/parser/javascript/node.js
index 94d8fbd..b7ae734 100644
--- a/src/js/parser/javascript/node.js
+++ b/src/js/parser/javascript/node.js
@@ -121,7 +121,7 @@ export default class Node {
 
     return this.deferredStep()
       .then(() => {
-        var box = text.getBBox(),
+        let box = text.getBBox(),
             margin = 5;
 
         text.transform(Snap.matrix()
@@ -161,7 +161,7 @@ export default class Node {
 
     return this.deferredStep()
       .then(() => {
-        var labelBox = label.getBBox(),
+        let labelBox = label.getBBox(),
             contentBox = content.getBBox();
 
         label.transform(Snap.matrix()
diff --git a/src/js/parser/javascript/regexp.js b/src/js/parser/javascript/regexp.js
index 9e2223b..6974482 100644
--- a/src/js/parser/javascript/regexp.js
+++ b/src/js/parser/javascript/regexp.js
@@ -19,7 +19,7 @@ export default {
       return match.render(matchContainer.group());
     }))
       .then(() => {
-        var containerBox,
+        let containerBox,
             paths;
 
         // Space matches vertically in the match container.
diff --git a/src/js/parser/javascript/root.js b/src/js/parser/javascript/root.js
index b7588d8..87567d4 100644
--- a/src/js/parser/javascript/root.js
+++ b/src/js/parser/javascript/root.js
@@ -24,7 +24,7 @@ export default {
     // Render the content of the regular expression.
     return this.regexp.render(this.container.group())
       .then(() => {
-        var box;
+        let box;
 
         // Move rendered regexp to account for flag label and to allow for
         // decorative elements.