diff --git a/STYLEGUIDE.md b/STYLEGUIDE.md
index 758fb0699b7..ec6211625a2 100644
--- a/STYLEGUIDE.md
+++ b/STYLEGUIDE.md
@@ -182,7 +182,7 @@ for (var key in keys) {
   // code
 }
 
-for (var i = 0, l = keys.length; i < l; i++) {
+for (var i = 0; i < keys.length; i++) {
   // code
 }
 
diff --git a/lib/jscs-rules/disallow-space-before-semicolon.js b/lib/jscs-rules/disallow-space-before-semicolon.js
index 85554a87f22..d755672d1cf 100644
--- a/lib/jscs-rules/disallow-space-before-semicolon.js
+++ b/lib/jscs-rules/disallow-space-before-semicolon.js
@@ -20,7 +20,7 @@ module.exports.prototype = {
 
   check: function(file, errors) {
     var lines = file.getLines();
-    for (var i = 0, l = lines.length; i < l; i++) {
+    for (var i = 0; i < lines.length; i++) {
       if (lines[i].match(/\s+;$/)) {
         errors.add('Spaces are disallowed before semicolons.', i + 1, lines[i].length - 2);
       }
diff --git a/packages/container/lib/container.js b/packages/container/lib/container.js
index 0b67cb7c93c..c2b4e09fcf0 100644
--- a/packages/container/lib/container.js
+++ b/packages/container/lib/container.js
@@ -226,7 +226,7 @@ function buildInjections(/* container, ...injections */) {
     var injections = [];
     var injection;
 
-    for (var i = 1, l = arguments.length; i < l; i++) {
+    for (var i = 1; i < arguments.length; i++) {
       if (arguments[i]) {
         injections = injections.concat(arguments[i]);
       }
@@ -234,7 +234,7 @@ function buildInjections(/* container, ...injections */) {
 
     container.registry.validateInjections(injections);
 
-    for (i = 0, l = injections.length; i < l; i++) {
+    for (i = 0; i < injections.length; i++) {
       injection = injections[i];
       hash[injection.property] = lookup(container, injection.fullName);
       if (!isSingleton(container, injection.fullName)) {
@@ -425,7 +425,7 @@ function eachDestroyable(container, callback) {
   var keys = Object.keys(cache);
   var key, value;
 
-  for (var i = 0, l = keys.length; i < l; i++) {
+  for (var i = 0; i < keys.length; i++) {
     key = keys[i];
     value = cache[key];
 
diff --git a/packages/container/lib/registry.js b/packages/container/lib/registry.js
index 01f838aa21d..5a29c3f5b23 100644
--- a/packages/container/lib/registry.js
+++ b/packages/container/lib/registry.js
@@ -672,7 +672,7 @@ Registry.prototype = {
 
     let localKnown = dictionary(null);
     let registeredNames = Object.keys(this.registrations);
-    for (let index = 0, length = registeredNames.length; index < length; index++) {
+    for (let index = 0; index < registeredNames.length; index++) {
       let fullName = registeredNames[index];
       let itemType = fullName.split(':')[0];
 
@@ -704,7 +704,7 @@ Registry.prototype = {
 
     var fullName;
 
-    for (var i = 0, length = injections.length; i < length; i++) {
+    for (var i = 0; i < injections.length; i++) {
       fullName = injections[i].fullName;
 
       if (!this.has(fullName)) {
diff --git a/packages/ember-application/lib/system/application.js b/packages/ember-application/lib/system/application.js
index d0a374c7a43..50121b46414 100644
--- a/packages/ember-application/lib/system/application.js
+++ b/packages/ember-application/lib/system/application.js
@@ -1128,7 +1128,7 @@ function logLibraryVersions() {
     var maxNameLength = Math.max.apply(this, nameLengths);
 
     debug('-------------------------------');
-    for (var i = 0, l = libs.length; i < l; i++) {
+    for (var i = 0; i < libs.length; i++) {
       var lib = libs[i];
       var spaces = new Array(maxNameLength - lib.name.length + 1).join(' ');
       debug([lib.name, spaces, ' : ', lib.version].join(''));
diff --git a/packages/ember-application/lib/system/resolver.js b/packages/ember-application/lib/system/resolver.js
index 99c99db071c..1fddfce6176 100644
--- a/packages/ember-application/lib/system/resolver.js
+++ b/packages/ember-application/lib/system/resolver.js
@@ -445,7 +445,7 @@ export default EmberObject.extend({
 
     let known = dictionary(null);
     let knownKeys = Object.keys(namespace);
-    for (let index = 0, length = knownKeys.length; index < length; index++) {
+    for (let index = 0; index < knownKeys.length; index++) {
       let name = knownKeys[index];
 
       if (typeRegexp.test(name)) {
diff --git a/packages/ember-htmlbars/lib/helpers/-join-classes.js b/packages/ember-htmlbars/lib/helpers/-join-classes.js
index c5c45625fb5..281d523f0f9 100644
--- a/packages/ember-htmlbars/lib/helpers/-join-classes.js
+++ b/packages/ember-htmlbars/lib/helpers/-join-classes.js
@@ -7,7 +7,7 @@
 export default function joinClasses(classNames) {
   var result = [];
 
-  for (let i = 0, l = classNames.length; i < l; i++) {
+  for (let i = 0; i < classNames.length; i++) {
     let className = classNames[i];
 
     if (className) {
diff --git a/packages/ember-htmlbars/lib/hooks/destroy-render-node.js b/packages/ember-htmlbars/lib/hooks/destroy-render-node.js
index 21473325276..fcfff351da6 100644
--- a/packages/ember-htmlbars/lib/hooks/destroy-render-node.js
+++ b/packages/ember-htmlbars/lib/hooks/destroy-render-node.js
@@ -10,7 +10,7 @@ export default function destroyRenderNode(renderNode) {
 
   var streamUnsubscribers = renderNode.streamUnsubscribers;
   if (streamUnsubscribers) {
-    for (let i = 0, l = streamUnsubscribers.length; i < l; i++) {
+    for (let i = 0; i < streamUnsubscribers.length; i++) {
       streamUnsubscribers[i]();
     }
   }
diff --git a/packages/ember-htmlbars/lib/hooks/invoke-helper.js b/packages/ember-htmlbars/lib/hooks/invoke-helper.js
index 9e8f44cfbf7..b1c9c8bb191 100644
--- a/packages/ember-htmlbars/lib/hooks/invoke-helper.js
+++ b/packages/ember-htmlbars/lib/hooks/invoke-helper.js
@@ -12,7 +12,7 @@ export default function invokeHelper(morph, env, scope, visitor, params, hash, h
       // We subscribe the morph to the helperStream here, and also subscribe
       // the helperStream to any params.
       let addedDependency = false;
-      for (var i = 0, l = params.length; i < l; i++) {
+      for (var i = 0; i < params.length; i++) {
         addedDependency = true;
         helperStream.addDependency(params[i]);
       }
diff --git a/packages/ember-htmlbars/lib/hooks/subexpr.js b/packages/ember-htmlbars/lib/hooks/subexpr.js
index 08b61cb1397..750ad9a7e61 100644
--- a/packages/ember-htmlbars/lib/hooks/subexpr.js
+++ b/packages/ember-htmlbars/lib/hooks/subexpr.js
@@ -23,7 +23,7 @@ export default function subexpr(env, scope, helperName, params, hash) {
 
   var helperStream = buildHelperStream(helper, params, hash, null, env, scope, label);
 
-  for (var i = 0, l = params.length; i < l; i++) {
+  for (var i = 0; i < params.length; i++) {
     helperStream.addDependency(params[i]);
   }
 
diff --git a/packages/ember-htmlbars/lib/morphs/morph.js b/packages/ember-htmlbars/lib/morphs/morph.js
index 70f6344106c..55ef0227629 100644
--- a/packages/ember-htmlbars/lib/morphs/morph.js
+++ b/packages/ember-htmlbars/lib/morphs/morph.js
@@ -47,7 +47,7 @@ proto.cleanup = function() {
   let toDestroy = this.emberToDestroy;
 
   if (toDestroy) {
-    for (var i = 0, l = toDestroy.length; i < l; i++) {
+    for (var i = 0; i < toDestroy.length; i++) {
       toDestroy[i].destroy();
     }
 
diff --git a/packages/ember-htmlbars/lib/streams/utils.js b/packages/ember-htmlbars/lib/streams/utils.js
index 6b6463dc083..85ff7d44631 100644
--- a/packages/ember-htmlbars/lib/streams/utils.js
+++ b/packages/ember-htmlbars/lib/streams/utils.js
@@ -3,10 +3,9 @@ import getValue from 'ember-htmlbars/hooks/get-value';
 // We don't want to leak mutable cells into helpers, which
 // are pure functions that can only work with values.
 export function getArrayValues(params) {
-  let l = params.length;
-  let out = new Array(l);
+  let out = new Array(params.length);
 
-  for (let i = 0; i < l; i++) {
+  for (let i = 0; i < params.length; i++) {
     out[i] = getValue(params[i]);
   }
 
diff --git a/packages/ember-htmlbars/tests/attr_nodes/sanitized_test.js b/packages/ember-htmlbars/tests/attr_nodes/sanitized_test.js
index b98e84d06f7..be33a661437 100644
--- a/packages/ember-htmlbars/tests/attr_nodes/sanitized_test.js
+++ b/packages/ember-htmlbars/tests/attr_nodes/sanitized_test.js
@@ -55,7 +55,7 @@ var badTags = [
     multipartTemplate: compile('<iframe src=\'{{protocol}}{{path}}\'></iframe>') }
 ];
 
-for (var i = 0, l = badTags.length; i < l; i++) {
+for (var i = 0; i < badTags.length; i++) {
   /* jshint -W083 */
   (function() {
     var subject = badTags[i];
diff --git a/packages/ember-htmlbars/tests/helpers/unbound_test.js b/packages/ember-htmlbars/tests/helpers/unbound_test.js
index a71c4e9637b..1d3b5d7fe4e 100644
--- a/packages/ember-htmlbars/tests/helpers/unbound_test.js
+++ b/packages/ember-htmlbars/tests/helpers/unbound_test.js
@@ -97,7 +97,7 @@ QUnit.test('should property escape unsafe hrefs', function() {
   runAppend(view);
 
   var links = view.$('a');
-  for (var i = 0, l = links.length; i < l; i++) {
+  for (var i = 0; i < links.length; i++) {
     var link = links[i];
     equal(link.protocol, 'unsafe:', 'properly escaped');
   }
diff --git a/packages/ember-metal-views/lib/htmlbars-renderer.js b/packages/ember-metal-views/lib/htmlbars-renderer.js
index ed9ad5d4155..6a7fdee8359 100755
--- a/packages/ember-metal-views/lib/htmlbars-renderer.js
+++ b/packages/ember-metal-views/lib/htmlbars-renderer.js
@@ -114,7 +114,7 @@ MorphSet.prototype.has = function(morph) {
 
 MorphSet.prototype.clear = function() {
   let morphs = this.morphs;
-  for (let i = 0, l = morphs.length; i < l; i++) {
+  for (let i = 0; i < morphs.length; i++) {
     morphs[i].seen = false;
   }
 
diff --git a/packages/ember-metal/lib/assign.js b/packages/ember-metal/lib/assign.js
index 33fe74b97d3..6f17f630969 100644
--- a/packages/ember-metal/lib/assign.js
+++ b/packages/ember-metal/lib/assign.js
@@ -16,13 +16,13 @@
   @public
 */
 export default function assign(original, ...args) {
-  for (let i = 0, l = args.length; i < l; i++) {
+  for (let i = 0; i < args.length; i++) {
     let arg = args[i];
     if (!arg) { continue; }
 
     let updates = Object.keys(arg);
 
-    for (let i = 0, l = updates.length; i < l; i++) {
+    for (let i = 0; i < updates.length; i++) {
       let prop = updates[i];
       original[prop] = arg[prop];
     }
diff --git a/packages/ember-metal/lib/chains.js b/packages/ember-metal/lib/chains.js
index 0d294243331..4987bbcfac0 100644
--- a/packages/ember-metal/lib/chains.js
+++ b/packages/ember-metal/lib/chains.js
@@ -37,7 +37,7 @@ ChainWatchers.prototype = {
   remove(key, node) {
     let nodes = this.chains[key];
     if (nodes) {
-      for (var i = 0, l = nodes.length; i < l; i++) {
+      for (var i = 0; i < nodes.length; i++) {
         if (nodes[i] === node) {
           nodes.splice(i, 1);
           break;
@@ -49,7 +49,7 @@ ChainWatchers.prototype = {
   has(key, node) {
     let nodes = this.chains[key];
     if (nodes) {
-      for (var i = 0, l = nodes.length; i < l; i++) {
+      for (var i = 0; i < nodes.length; i++) {
         if (nodes[i] === node) {
           return true;
         }
@@ -85,7 +85,7 @@ ChainWatchers.prototype = {
       affected = [];
     }
 
-    for (let i = 0, l = nodes.length; i < l; i++) {
+    for (let i = 0; i < nodes.length; i++) {
       nodes[i].notify(revalidate, affected);
     }
 
@@ -94,7 +94,7 @@ ChainWatchers.prototype = {
     }
 
     // we gather callbacks so we don't notify them during revalidation
-    for (let i = 0, l = affected.length; i < l; i += 2) {
+    for (let i = 0; i < affected.length; i += 2) {
       let obj  = affected[i];
       let path = affected[i + 1];
       callback(obj, path);
diff --git a/packages/ember-metal/lib/computed.js b/packages/ember-metal/lib/computed.js
index 17f0fc78e38..72395c6fa08 100644
--- a/packages/ember-metal/lib/computed.js
+++ b/packages/ember-metal/lib/computed.js
@@ -265,7 +265,7 @@ ComputedPropertyPrototype.property = function() {
   };
 
   args = [];
-  for (var i = 0, l = arguments.length; i < l; i++) {
+  for (var i = 0; i < arguments.length; i++) {
     expandProperties(arguments[i], addArg);
   }
 
diff --git a/packages/ember-metal/lib/dependent_keys.js b/packages/ember-metal/lib/dependent_keys.js
index 227cec1e1c4..eff8e3ea606 100644
--- a/packages/ember-metal/lib/dependent_keys.js
+++ b/packages/ember-metal/lib/dependent_keys.js
@@ -19,13 +19,13 @@ import {
 export function addDependentKeys(desc, obj, keyName, meta) {
   // the descriptor has a list of dependent keys, so
   // add all of its dependent keys.
-  var idx, len, depKey;
+  var idx, depKey;
   var depKeys = desc._dependentKeys;
   if (!depKeys) {
     return;
   }
 
-  for (idx = 0, len = depKeys.length; idx < len; idx++) {
+  for (idx = 0; idx < depKeys.length; idx++) {
     depKey = depKeys[idx];
     // Increment the number of times depKey depends on keyName.
     meta.writeDeps(depKey, keyName, (meta.peekDeps(depKey, keyName)|| 0) + 1);
@@ -38,12 +38,12 @@ export function removeDependentKeys(desc, obj, keyName, meta) {
   // the descriptor has a list of dependent keys, so
   // remove all of its dependent keys.
   var depKeys = desc._dependentKeys;
-  var idx, len, depKey;
+  var idx, depKey;
   if (!depKeys) {
     return;
   }
 
-  for (idx = 0, len = depKeys.length; idx < len; idx++) {
+  for (idx = 0; idx < depKeys.length; idx++) {
     depKey = depKeys[idx];
     // Decrement the number of times depKey depends on keyName.
     meta.writeDeps(depKey, keyName, (meta.peekDeps(depKey, keyName) || 0) - 1);
diff --git a/packages/ember-metal/lib/events.js b/packages/ember-metal/lib/events.js
index 36ad4c1d3ad..5e40cb4324d 100644
--- a/packages/ember-metal/lib/events.js
+++ b/packages/ember-metal/lib/events.js
@@ -260,7 +260,7 @@ export function listenersFor(obj, eventName) {
 
   if (!actions) { return ret; }
 
-  for (var i = 0, l = actions.length; i < l; i += 3) {
+  for (var i = 0; i < actions.length; i += 3) {
     var target = actions[i];
     var method = actions[i + 1];
     ret.push([target, method]);
diff --git a/packages/ember-metal/lib/get_properties.js b/packages/ember-metal/lib/get_properties.js
index 36fe8b42dec..7a27080aaec 100644
--- a/packages/ember-metal/lib/get_properties.js
+++ b/packages/ember-metal/lib/get_properties.js
@@ -32,7 +32,7 @@ export default function getProperties(obj) {
     i = 0;
     propertyNames = arguments[1];
   }
-  for (var len = propertyNames.length; i < len; i++) {
+  for (; i < propertyNames.length; i++) {
     ret[propertyNames[i]] = get(obj, propertyNames[i]);
   }
   return ret;
diff --git a/packages/ember-metal/lib/instrumentation.js b/packages/ember-metal/lib/instrumentation.js
index ca9337686ae..43340abda33 100644
--- a/packages/ember-metal/lib/instrumentation.js
+++ b/packages/ember-metal/lib/instrumentation.js
@@ -54,7 +54,7 @@ var populateListeners = function(name) {
   var listeners = [];
   var subscriber;
 
-  for (var i = 0, l = subscribers.length; i < l; i++) {
+  for (var i = 0; i < subscribers.length; i++) {
     subscriber = subscribers[i];
     if (subscriber.regex.test(name)) {
       listeners.push(subscriber.object);
@@ -137,19 +137,18 @@ export function _instrumentStart(name, _payload) {
     console.time(timeName);
   }
 
-  var l = listeners.length;
-  var beforeValues = new Array(l);
+  var beforeValues = new Array(listeners.length);
   var i, listener;
   var timestamp = time();
-  for (i = 0; i < l; i++) {
+  for (i = 0; i < listeners.length; i++) {
     listener = listeners[i];
     beforeValues[i] = listener.before(name, timestamp, payload);
   }
 
   return function _instrumentEnd() {
-    var i, l, listener;
+    var i, listener;
     var timestamp = time();
-    for (i = 0, l = listeners.length; i < l; i++) {
+    for (i = 0; i < listeners.length; i++) {
       listener = listeners[i];
       listener.after(name, timestamp, payload, beforeValues[i]);
     }
@@ -177,7 +176,7 @@ export function subscribe(pattern, object) {
   var path;
   var regex = [];
 
-  for (var i = 0, l = paths.length; i < l; i++) {
+  for (var i = 0; i < paths.length; i++) {
     path = paths[i];
     if (path === '*') {
       regex.push('[^\\.]*');
@@ -213,7 +212,7 @@ export function subscribe(pattern, object) {
 export function unsubscribe(subscriber) {
   var index;
 
-  for (var i = 0, l = subscribers.length; i < l; i++) {
+  for (var i = 0; i < subscribers.length; i++) {
     if (subscribers[i] === subscriber) {
       index = i;
     }
diff --git a/packages/ember-metal/lib/map.js b/packages/ember-metal/lib/map.js
index 740983d2a36..919635e3db9 100644
--- a/packages/ember-metal/lib/map.js
+++ b/packages/ember-metal/lib/map.js
@@ -182,10 +182,9 @@ OrderedSet.prototype = {
     if (this.size === 0) { return; }
 
     var list = this.list;
-    var length = arguments.length;
     var i;
 
-    if (length === 2) {
+    if (arguments.length === 2) {
       for (i = 0; i < list.length; i++) {
         fn.call(arguments[1], list[i]);
       }
@@ -382,11 +381,10 @@ Map.prototype = {
 
     if (this.size === 0) { return; }
 
-    var length = arguments.length;
     var map = this;
     var cb, thisArg;
 
-    if (length === 2) {
+    if (arguments.length === 2) {
       thisArg = arguments[1];
       cb = function(key) {
         callback.call(thisArg, map.get(key), key, map);
diff --git a/packages/ember-metal/lib/merge.js b/packages/ember-metal/lib/merge.js
index 5747c94b6df..9ca7cfb0127 100644
--- a/packages/ember-metal/lib/merge.js
+++ b/packages/ember-metal/lib/merge.js
@@ -29,9 +29,8 @@ export default function merge(original, updates) {
 
   var props = Object.keys(updates);
   var prop;
-  var length = props.length;
 
-  for (var i = 0; i < length; i++) {
+  for (var i = 0; i < props.length; i++) {
     prop = props[i];
     original[prop] = updates[prop];
   }
diff --git a/packages/ember-metal/lib/mixin.js b/packages/ember-metal/lib/mixin.js
index 5876f2aee3e..47355db34c3 100644
--- a/packages/ember-metal/lib/mixin.js
+++ b/packages/ember-metal/lib/mixin.js
@@ -231,7 +231,7 @@ function mergeMixins(mixins, m, descs, values, base, keys) {
     delete values[keyName];
   }
 
-  for (var i = 0, l = mixins.length; i < l; i++) {
+  for (var i = 0; i < mixins.length; i++) {
     currentMixin = mixins[i];
     assert(
       `Expected hash or Mixin instance, got ${Object.prototype.toString.call(currentMixin)}`,
@@ -344,7 +344,7 @@ function updateObserversAndListeners(obj, key, observerOrListener, pathsKey, upd
   var paths = observerOrListener[pathsKey];
 
   if (paths) {
-    for (var i = 0, l = paths.length; i < l; i++) {
+    for (var i = 0; i < paths.length; i++) {
       updateMethod(obj, paths[i], null, key);
     }
   }
@@ -384,7 +384,7 @@ function applyMixin(obj, mixins, partial) {
   // * Copying `toString` in broken browsers
   mergeMixins(mixins, m, descs, values, obj, keys);
 
-  for (var i = 0, l = keys.length; i < l; i++) {
+  for (var i = 0; i < keys.length; i++) {
     key = keys[i];
     if (key === 'constructor' || !values.hasOwnProperty(key)) { continue; }
 
@@ -553,11 +553,10 @@ MixinPrototype.reopen = function() {
     this.mixins = [];
   }
 
-  var len = arguments.length;
   var mixins = this.mixins;
   var idx;
 
-  for (idx = 0; idx < len; idx++) {
+  for (idx = 0; idx < arguments.length; idx++) {
     currentMixin = arguments[idx];
     assert(
       `Expected hash or Mixin instance, got ${Object.prototype.toString.call(currentMixin)}`,
@@ -805,7 +804,7 @@ export function observer(...args) {
 export function _immediateObserver() {
   deprecate('Usage of `Ember.immediateObserver` is deprecated, use `Ember.observer` instead.', false, { id: 'ember-metal.immediate-observer', until: '3.0.0' });
 
-  for (var i = 0, l = arguments.length; i < l; i++) {
+  for (var i = 0; i < arguments.length; i++) {
     var arg = arguments[i];
     assert(
       'Immediate observers must observe internal properties only, not properties on other objects.',
diff --git a/packages/ember-metal/lib/observer_set.js b/packages/ember-metal/lib/observer_set.js
index 0350522a3c3..a59b5dbea5b 100644
--- a/packages/ember-metal/lib/observer_set.js
+++ b/packages/ember-metal/lib/observer_set.js
@@ -50,9 +50,9 @@ ObserverSet.prototype.add = function(sender, keyName, eventName) {
 
 ObserverSet.prototype.flush = function() {
   var observers = this.observers;
-  var i, len, observer, sender;
+  var i, observer, sender;
   this.clear();
-  for (i = 0, len = observers.length; i < len; ++i) {
+  for (i = 0; i < observers.length; ++i) {
     observer = observers[i];
     sender = observer.sender;
     if (sender.isDestroying || sender.isDestroyed) { continue; }
diff --git a/packages/ember-metal/lib/property_get.js b/packages/ember-metal/lib/property_get.js
index 70d81ab5c4c..b9504c7d6f5 100644
--- a/packages/ember-metal/lib/property_get.js
+++ b/packages/ember-metal/lib/property_get.js
@@ -73,9 +73,8 @@ export function get(obj, keyName) {
 export function _getPath(root, path) {
   let obj = root;
   let parts = path.split('.');
-  let len = parts.length;
 
-  for (let i = 0; i < len; i++) {
+  for (let i = 0; i < parts.length; i++) {
     if (obj == null) {
       return obj;
     }
diff --git a/packages/ember-metal/lib/set_properties.js b/packages/ember-metal/lib/set_properties.js
index 53b68fa0930..3deb7d11b16 100644
--- a/packages/ember-metal/lib/set_properties.js
+++ b/packages/ember-metal/lib/set_properties.js
@@ -28,7 +28,7 @@ export default function setProperties(obj, properties) {
     var props = Object.keys(properties);
     var propertyName;
 
-    for (var i = 0, l = props.length; i < l; i++) {
+    for (var i = 0; i < props.length; i++) {
       propertyName = props[i];
 
       set(obj, propertyName, properties[propertyName]);
diff --git a/packages/ember-metal/lib/streams/stream.js b/packages/ember-metal/lib/streams/stream.js
index 902a156c8d3..1c4bf1f1137 100644
--- a/packages/ember-metal/lib/streams/stream.js
+++ b/packages/ember-metal/lib/streams/stream.js
@@ -295,7 +295,7 @@ BasicStream.prototype = {
       var dependencies = this.dependencies;
 
       if (dependencies) {
-        for (var i = 0, l = dependencies.length; i < l; i++) {
+        for (var i = 0; i < dependencies.length; i++) {
           dependencies[i](prune);
         }
       }
diff --git a/packages/ember-metal/lib/streams/utils.js b/packages/ember-metal/lib/streams/utils.js
index ff65e4a3496..b1b6ddc36d4 100644
--- a/packages/ember-metal/lib/streams/utils.js
+++ b/packages/ember-metal/lib/streams/utils.js
@@ -80,9 +80,8 @@ export function read(object) {
                  and replaced with the stream's current value.
  */
 export function readArray(array) {
-  var length = array.length;
-  var ret = new Array(length);
-  for (var i = 0; i < length; i++) {
+  var ret = new Array(array.length);
+  for (var i = 0; i < array.length; i++) {
     ret[i] = read(array[i]);
   }
   return ret;
@@ -120,10 +119,9 @@ export function readHash(object) {
                    otherwise.
 */
 export function scanArray(array) {
-  var length = array.length;
   var containsStream = false;
 
-  for (var i = 0; i < length; i++) {
+  for (var i = 0; i < array.length; i++) {
     if (isStream(array[i])) {
       containsStream = true;
       break;
@@ -196,7 +194,7 @@ export function concat(array, separator) {
   if (hasStream) {
     let stream = new ConcatStream(array, separator);
 
-    for (let i = 0, l = array.length; i < l; i++) {
+    for (let i = 0; i < array.length; i++) {
       addDependency(stream, array[i]);
     }
 
@@ -209,7 +207,7 @@ export function concat(array, separator) {
 export function labelsFor(streams) {
   var labels =  [];
 
-  for (var i = 0, l = streams.length; i < l; i++) {
+  for (var i = 0; i < streams.length; i++) {
     var stream = streams[i];
     labels.push(labelFor(stream));
   }
@@ -275,7 +273,7 @@ export function zip(streams, callback, label) {
     return `${label}(${labelsFor(streams)})`;
   });
 
-  for (var i = 0, l = streams.length; i < l; i++) {
+  for (var i = 0; i < streams.length; i++) {
     stream.addDependency(streams[i]);
   }
 
diff --git a/packages/ember-metal/lib/utils.js b/packages/ember-metal/lib/utils.js
index d4393586922..f93bf83353d 100644
--- a/packages/ember-metal/lib/utils.js
+++ b/packages/ember-metal/lib/utils.js
@@ -298,10 +298,9 @@ export function wrap(func, superFunc) {
 function _wrap(func, superFunc) {
   function superWrapper() {
     let orig = this._super;
-    let length = arguments.length;
     let ret;
     this._super = superFunc;
-    switch (length) {
+    switch (arguments.length) {
       case 0:  ret = func.call(this); break;
       case 1:  ret = func.call(this, arguments[0]); break;
       case 2:  ret = func.call(this, arguments[0], arguments[1]); break;
@@ -311,8 +310,8 @@ function _wrap(func, superFunc) {
       default:
         // v8 bug potentially incorrectly deopts this function: https://code.google.com/p/v8/issues/detail?id=3709
         // we may want to keep this around till this ages out on mobile
-        let args = new Array(length);
-        for (var x = 0; x < length; x++) {
+        let args = new Array(arguments.length);
+        for (var x = 0; x < arguments.length; x++) {
           args[x] = arguments[x];
         }
         ret = func.apply(this, args);
diff --git a/packages/ember-metal/tests/map_test.js b/packages/ember-metal/tests/map_test.js
index bc72e7a1299..e75c6c3cbee 100644
--- a/packages/ember-metal/tests/map_test.js
+++ b/packages/ember-metal/tests/map_test.js
@@ -34,7 +34,7 @@ function testMap(nameAndFunc) {
   var mapHasEntries = function(entries, theMap) {
     theMap = theMap || map;
 
-    for (var i = 0, l = entries.length; i < l; i++) {
+    for (var i = 0; i < entries.length; i++) {
       equal(theMap.get(entries[i][0]), entries[i][1]);
       equal(theMap.has(entries[i][0]), true);
     }
diff --git a/packages/ember-routing-htmlbars/lib/keywords/element-action.js b/packages/ember-routing-htmlbars/lib/keywords/element-action.js
index ac94580cc78..c7f7c6375a2 100644
--- a/packages/ember-routing-htmlbars/lib/keywords/element-action.js
+++ b/packages/ember-routing-htmlbars/lib/keywords/element-action.js
@@ -21,7 +21,7 @@ export default {
     );
 
     var actionArgs = [];
-    for (var i = 1, l = params.length; i < l; i++) {
+    for (var i = 1; i < params.length; i++) {
       actionArgs.push(readUnwrappedModel(params[i]));
     }
 
@@ -136,7 +136,7 @@ function isAllowedEvent(event, allowedKeys) {
     return true;
   }
 
-  for (var i = 0, l = MODIFIERS.length; i < l; i++) {
+  for (var i = 0; i < MODIFIERS.length; i++) {
     if (event[MODIFIERS[i] + 'Key'] && allowedKeys.indexOf(MODIFIERS[i]) === -1) {
       return false;
     }
diff --git a/packages/ember-routing-views/lib/components/link-to.js b/packages/ember-routing-views/lib/components/link-to.js
index 98333e7d7d8..f76797d91f0 100644
--- a/packages/ember-routing-views/lib/components/link-to.js
+++ b/packages/ember-routing-views/lib/components/link-to.js
@@ -559,7 +559,7 @@ let LinkComponent = EmberComponent.extend({
     currentWhen = currentWhen || get(this, 'qualifiedRouteName');
     currentWhen = currentWhen.split(' ');
 
-    for (let i = 0, len = currentWhen.length; i < len; i++) {
+    for (let i = 0; i < currentWhen.length; i++) {
       if (routing.isActiveForRoute(models, resolvedQueryParams, currentWhen[i], routerState, isCurrentWhenSpecified)) {
         return get(this, 'activeClass');
       }
@@ -717,7 +717,7 @@ let LinkComponent = EmberComponent.extend({
 
   _modelsAreLoaded: computed('models', function computeLinkToComponentModelsAreLoaded() {
     let models = get(this, 'models');
-    for (let i = 0, l = models.length; i < l; i++) {
+    for (let i = 0; i < models.length; i++) {
       if (models[i] == null) { return false; }
     }
 
diff --git a/packages/ember-routing/lib/services/routing.js b/packages/ember-routing/lib/services/routing.js
index 8991c1819e8..77b064d0e83 100644
--- a/packages/ember-routing/lib/services/routing.js
+++ b/packages/ember-routing/lib/services/routing.js
@@ -92,7 +92,7 @@ export default Service.extend({
 
 function numberOfContextsAcceptedByHandler(handler, handlerInfos) {
   var req = 0;
-  for (var i = 0, l = handlerInfos.length; i < l; i++) {
+  for (var i = 0; i < handlerInfos.length; i++) {
     req = req + handlerInfos[i].names.length;
     if (handlerInfos[i].handler === handler) {
       break;
diff --git a/packages/ember-routing/lib/system/dsl.js b/packages/ember-routing/lib/system/dsl.js
index a7eeaba35eb..bf1283aeb1d 100644
--- a/packages/ember-routing/lib/system/dsl.js
+++ b/packages/ember-routing/lib/system/dsl.js
@@ -92,7 +92,7 @@ DSL.prototype = {
     }
 
     return function(match) {
-      for (var i = 0, l = dslMatches.length; i < l; i++) {
+      for (var i = 0; i < dslMatches.length; i++) {
         var dslMatch = dslMatches[i];
         match(dslMatch[0]).to(dslMatch[1], dslMatch[2]);
       }
diff --git a/packages/ember-routing/lib/system/route.js b/packages/ember-routing/lib/system/route.js
index 3f3b88f24a4..91390bc7678 100644
--- a/packages/ember-routing/lib/system/route.js
+++ b/packages/ember-routing/lib/system/route.js
@@ -276,14 +276,13 @@ var Route = EmberObject.extend(ActionHandler, Evented, {
     }
 
     var qps = get(this, '_qp.qps');
-    var len = qps.length;
 
     var namePaths = new Array(names.length);
-    for (var a = 0, nlen = names.length; a < nlen; ++a) {
+    for (var a = 0; a < names.length; ++a) {
       namePaths[a] = `${handlerInfo.name}.${names[a]}`;
     }
 
-    for (var i = 0; i < len; ++i) {
+    for (var i = 0; i < qps.length; ++i) {
       var qp = qps[i];
       if (qp.scope === 'model') {
         qp.parts = namePaths;
@@ -757,7 +756,7 @@ var Route = EmberObject.extend(ActionHandler, Evented, {
       var qpMap = get(this, '_qp').map;
 
       var totalChanged = Object.keys(changed).concat(Object.keys(removed));
-      for (var i = 0, len = totalChanged.length; i < len; ++i) {
+      for (var i = 0; i < totalChanged.length; ++i) {
         var qp = qpMap[totalChanged[i]];
         if (qp && get(this._optionsForQueryParam(qp), 'refreshModel')) {
           this.refresh();
@@ -781,7 +780,7 @@ var Route = EmberObject.extend(ActionHandler, Evented, {
 
       stashParamNames(router, handlerInfos);
 
-      for (var i = 0, len = qpMeta.qps.length; i < len; ++i) {
+      for (var i = 0; i < qpMeta.qps.length; ++i) {
         var qp = qpMeta.qps[i];
         var route = qp.route;
         var controller = route.controller;
@@ -2091,7 +2090,7 @@ function handlerInfoFor(route, handlerInfos, _offset) {
 
   var offset = _offset || 0;
   var current;
-  for (var i = 0, l = handlerInfos.length; i < l; i++) {
+  for (var i = 0; i < handlerInfos.length; i++) {
     current = handlerInfos[i].handler;
     if (current === route) { return handlerInfos[i + offset]; }
   }
@@ -2207,7 +2206,7 @@ function getQueryParamsFor(route, state) {
   // Copy over all the query params for this route/controller into params hash.
   var qpMeta = get(route, '_qp');
   var qps = qpMeta.qps;
-  for (var i = 0, len = qps.length; i < len; ++i) {
+  for (var i = 0; i < qps.length; ++i) {
     // Put deserialized qp on params hash.
     var qp = qps[i];
 
diff --git a/packages/ember-routing/lib/system/router.js b/packages/ember-routing/lib/system/router.js
index 21feadeb147..7f29324af70 100644
--- a/packages/ember-routing/lib/system/router.js
+++ b/packages/ember-routing/lib/system/router.js
@@ -669,7 +669,7 @@ var EmberRouter = EmberObject.extend(Evented, {
     var routerjs = this.router;
     var recogHandlerInfos = routerjs.recognizer.handlersFor(leafRouteName);
 
-    for (var i = 0, len = recogHandlerInfos.length; i < len; ++i) {
+    for (var i = 0; i < recogHandlerInfos.length; ++i) {
       var recogHandler = recogHandlerInfos[i];
       var route = routerjs.getHandler(recogHandler.handler);
       var qpMeta = get(route, '_qp');
@@ -692,7 +692,7 @@ var EmberRouter = EmberObject.extend(Evented, {
     var appCache = this._bucketCache;
     stashParamNames(this, handlerInfos);
 
-    for (var i = 0, len = handlerInfos.length; i < len; ++i) {
+    for (var i = 0; i < handlerInfos.length; ++i) {
       var route = handlerInfos[i].handler;
       var qpMeta = get(route, '_qp');
 
@@ -944,7 +944,7 @@ function calculatePostTransitionState(emberRouter, leafRouteName, contexts) {
   var handlerInfos = state.handlerInfos;
   var params = state.params;
 
-  for (var i = 0, len = handlerInfos.length; i < len; ++i) {
+  for (var i = 0; i < handlerInfos.length; ++i) {
     var handlerInfo = handlerInfos[i];
     if (!handlerInfo.isResolved) {
       handlerInfo = handlerInfo.becomeResolved(null, handlerInfo.context);
@@ -1047,7 +1047,7 @@ EmberRouter.reopenClass({
     // ['foo', 'foo.bar.baz'] => 'foo.bar.baz', not 'foo.foo.bar.baz'
 
     function intersectionMatches(a1, a2) {
-      for (var i = 0, len = a1.length; i < len; ++i) {
+      for (var i = 0; i < a1.length; ++i) {
         if (a1[i] !== a2[i]) {
           return false;
         }
@@ -1056,7 +1056,7 @@ EmberRouter.reopenClass({
     }
 
     var name, nameParts, oldNameParts;
-    for (var i = 1, l = handlerInfos.length; i < l; i++) {
+    for (var i = 1; i < handlerInfos.length; i++) {
       name = handlerInfos[i].name;
       nameParts = name.split('.');
       oldNameParts = slice.call(path);
diff --git a/packages/ember-routing/lib/utils.js b/packages/ember-routing/lib/utils.js
index 76240e0ee29..b7ca4747e97 100644
--- a/packages/ember-routing/lib/utils.js
+++ b/packages/ember-routing/lib/utils.js
@@ -29,7 +29,7 @@ export function stashParamNames(router, handlerInfos) {
   var recogHandlers = router.router.recognizer.handlersFor(targetRouteName);
   var dynamicParent = null;
 
-  for (var i = 0, len = handlerInfos.length; i < len; ++i) {
+  for (var i = 0; i < handlerInfos.length; ++i) {
     var handlerInfo = handlerInfos[i];
     var names = recogHandlers[i].names;
 
@@ -59,7 +59,7 @@ function _calculateCacheValuePrefix(prefix, part) {
   var prefixParts = prefix.split('.');
   var currPrefix = '';
 
-  for (var i = 0, len = prefixParts.length; i < len; i++) {
+  for (var i = 0; i < prefixParts.length; i++) {
     var currPart = prefixParts.slice(0, i + 1).join('.');
     if (part.indexOf(currPart) !== 0) {
       break;
@@ -76,7 +76,7 @@ function _calculateCacheValuePrefix(prefix, part) {
 export function calculateCacheKey(prefix, _parts, values) {
   var parts = _parts || [];
   var suffixes = '';
-  for (var i = 0, len = parts.length; i < len; ++i) {
+  for (var i = 0; i < parts.length; ++i) {
     var part = parts[i];
     var cacheValuePrefix = _calculateCacheValuePrefix(prefix, part);
     var value;
@@ -134,7 +134,7 @@ export function normalizeControllerQueryParams(queryParams) {
 
   var qpMap = queryParams._qpMap = {};
 
-  for (var i = 0, len = queryParams.length; i < len; ++i) {
+  for (var i = 0; i < queryParams.length; ++i) {
     accumulateQueryParamDescriptors(queryParams[i], qpMap);
   }
 
diff --git a/packages/ember-runtime/lib/ext/function.js b/packages/ember-runtime/lib/ext/function.js
index c89bf9abc0c..98a84cb7d0f 100644
--- a/packages/ember-runtime/lib/ext/function.js
+++ b/packages/ember-runtime/lib/ext/function.js
@@ -114,7 +114,7 @@ if (Ember.EXTEND_PROTOTYPES === true || Ember.EXTEND_PROTOTYPES.Function) {
       'Immediate observers must observe internal properties only, ' +
       'not properties on other objects.',
       function checkIsInternalProperty() {
-        for (var i = 0, l = arguments.length; i < l; i++) {
+        for (var i = 0; i < arguments.length; i++) {
           if (arguments[i].indexOf('.') !== -1) {
             return false;
           }
diff --git a/packages/ember-runtime/lib/inject.js b/packages/ember-runtime/lib/inject.js
index a2670c44f84..a99882ee34a 100644
--- a/packages/ember-runtime/lib/inject.js
+++ b/packages/ember-runtime/lib/inject.js
@@ -49,7 +49,7 @@ export function createInjectionHelper(type, validator) {
 export function validatePropertyInjections(factory) {
   var proto = factory.proto();
   var types = [];
-  var key, desc, validator, i, l;
+  var key, desc, validator, i;
 
   for (key in proto) {
     desc = proto[key];
@@ -59,7 +59,7 @@ export function validatePropertyInjections(factory) {
   }
 
   if (types.length) {
-    for (i = 0, l = types.length; i < l; i++) {
+    for (i = 0; i < types.length; i++) {
       validator = typeValidators[types[i]];
 
       if (typeof validator === 'function') {
diff --git a/packages/ember-runtime/lib/system/core_object.js b/packages/ember-runtime/lib/system/core_object.js
index 59e2ddab434..e9417f7f376 100644
--- a/packages/ember-runtime/lib/system/core_object.js
+++ b/packages/ember-runtime/lib/system/core_object.js
@@ -82,7 +82,7 @@ function makeCtor() {
       var concatenatedProperties = this.concatenatedProperties;
       var mergedProperties = this.mergedProperties;
 
-      for (var i = 0, l = props.length; i < l; i++) {
+      for (var i = 0; i < props.length; i++) {
         var properties = props[i];
 
         assert(
@@ -99,7 +99,7 @@ function makeCtor() {
 
         var keyNames = Object.keys(properties);
 
-        for (var j = 0, ll = keyNames.length; j < ll; j++) {
+        for (var j = 0; j < keyNames.length; j++) {
           var keyName = keyNames[j];
           var value = properties[keyName];
 
@@ -169,17 +169,15 @@ function makeCtor() {
 
     finishPartial(this, m);
 
-    var length = arguments.length;
-
-    if (length === 0) {
+    if (arguments.length === 0) {
       this.init();
-    } else if (length === 1) {
+    } else if (arguments.length === 1) {
       this.init(arguments[0]);
     } else {
       // v8 bug potentially incorrectly deopts this function: https://code.google.com/p/v8/issues/detail?id=3709
       // we may want to keep this around till this ages out on mobile
-      var args = new Array(length);
-      for (var x = 0; x < length; x++) {
+      var args = new Array(arguments.length);
+      for (var x = 0; x < arguments.length; x++) {
         args[x] = arguments[x];
       }
       this.init.apply(this, args);
@@ -888,7 +886,7 @@ var ClassMixinProps = {
 
     var properties = get(this, '_computedProperties');
 
-    for (var i = 0, length = properties.length; i < length; i++) {
+    for (var i = 0; i < properties.length; i++) {
       property = properties[i];
       callback.call(binding || this, property.name, property.meta || empty);
     }
diff --git a/packages/ember-runtime/lib/system/namespace.js b/packages/ember-runtime/lib/system/namespace.js
index 3c2f479b949..3cfe8fb6f99 100644
--- a/packages/ember-runtime/lib/system/namespace.js
+++ b/packages/ember-runtime/lib/system/namespace.js
@@ -205,7 +205,7 @@ function processAllNamespaces() {
     var namespaces = Namespace.NAMESPACES;
     var namespace;
 
-    for (var i = 0, l = namespaces.length; i < l; i++) {
+    for (var i = 0; i < namespaces.length; i++) {
       namespace = namespaces[i];
       processNamespace([namespace.toString()], namespace, {});
     }
diff --git a/packages/ember-runtime/lib/system/string.js b/packages/ember-runtime/lib/system/string.js
index 80231ff0df9..6ffd95cdb70 100644
--- a/packages/ember-runtime/lib/system/string.js
+++ b/packages/ember-runtime/lib/system/string.js
@@ -42,7 +42,7 @@ var CLASSIFY_CACHE = new Cache(1000, function(str) {
     return initialChar + (chr ? chr.toUpperCase() : '');
   };
   var parts = str.split('/');
-  for (var i = 0, len = parts.length; i < len; i++) {
+  for (var i = 0; i < parts.length; i++) {
     parts[i] = parts[i]
       .replace(STRING_CLASSIFY_REGEXP_1, replace1)
       .replace(STRING_CLASSIFY_REGEXP_2, replace2);
@@ -81,7 +81,7 @@ function _fmt(str, formats) {
   if (!isArray(cachedFormats) || arguments.length > 2) {
     cachedFormats = new Array(arguments.length - 1);
 
-    for (var i = 1, l = arguments.length; i < l; i++) {
+    for (var i = 1; i < arguments.length; i++) {
       cachedFormats[i - 1] = arguments[i];
     }
   }
diff --git a/packages/ember-runtime/tests/system/object/destroy_test.js b/packages/ember-runtime/tests/system/object/destroy_test.js
index 8d0c2579f07..b560271b807 100644
--- a/packages/ember-runtime/tests/system/object/destroy_test.js
+++ b/packages/ember-runtime/tests/system/object/destroy_test.js
@@ -137,7 +137,7 @@ QUnit.test('destroyed objects should not see each others changes during teardown
 
   run(function () {
     var keys = Object.keys(objs);
-    for (var i = 0, l = keys.length; i < l; i++) {
+    for (var i = 0; i < keys.length; i++) {
       objs[keys[i]].destroy();
     }
   });
diff --git a/packages/ember-template-compiler/lib/plugins/assert-no-view-and-controller-paths.js b/packages/ember-template-compiler/lib/plugins/assert-no-view-and-controller-paths.js
index 3f5dd99791e..30e7880ea21 100644
--- a/packages/ember-template-compiler/lib/plugins/assert-no-view-and-controller-paths.js
+++ b/packages/ember-template-compiler/lib/plugins/assert-no-view-and-controller-paths.js
@@ -32,8 +32,8 @@ function assertHash(moduleName, node, hash) {
   if (!hash || !hash.pairs) {
     return;
   }
-  var i, l, pair, paths;
-  for (i = 0, l = hash.pairs.length;i < l;i++) {
+  var i, pair, paths;
+  for (i = 0; i < hash.pairs.length; i++) {
     pair = hash.pairs[i];
     paths = pair.value.params;
     assertPaths(moduleName, pair, paths);
@@ -44,8 +44,8 @@ function assertPaths(moduleName, node, paths) {
   if (!paths) {
     return;
   }
-  var i, l, path;
-  for (i = 0, l = paths.length;i < l;i++) {
+  var i, path;
+  for (i = 0; i < paths.length; i++) {
     path = paths[i];
     assertPath(moduleName, node, path);
   }
diff --git a/packages/ember-template-compiler/lib/plugins/transform-component-attrs-into-mut.js b/packages/ember-template-compiler/lib/plugins/transform-component-attrs-into-mut.js
index b8d2effad27..75b431eefb4 100644
--- a/packages/ember-template-compiler/lib/plugins/transform-component-attrs-into-mut.js
+++ b/packages/ember-template-compiler/lib/plugins/transform-component-attrs-into-mut.js
@@ -32,7 +32,7 @@ function validate(node) {
 }
 
 function each(list, callback) {
-  for (var i = 0, l = list.length; i < l; i++) {
+  for (var i = 0; i < list.length; i++) {
     callback(list[i]);
   }
 }
diff --git a/packages/ember-template-compiler/lib/plugins/transform-component-curly-to-readonly.js b/packages/ember-template-compiler/lib/plugins/transform-component-curly-to-readonly.js
index a63705b810f..3254ca20c79 100644
--- a/packages/ember-template-compiler/lib/plugins/transform-component-curly-to-readonly.js
+++ b/packages/ember-template-compiler/lib/plugins/transform-component-curly-to-readonly.js
@@ -31,7 +31,7 @@ function validate(node) {
 }
 
 function each(list, callback) {
-  for (var i = 0, l = list.length; i < l; i++) {
+  for (var i = 0; i < list.length; i++) {
     callback(list[i]);
   }
 }
diff --git a/packages/ember-template-compiler/lib/plugins/transform-each-into-collection.js b/packages/ember-template-compiler/lib/plugins/transform-each-into-collection.js
index 28aaff99e48..2c63bd27764 100644
--- a/packages/ember-template-compiler/lib/plugins/transform-each-into-collection.js
+++ b/packages/ember-template-compiler/lib/plugins/transform-each-into-collection.js
@@ -57,7 +57,7 @@ function validate(node) {
 }
 
 function any(list, predicate) {
-  for (var i = 0, l = list.length; i < l; i++) {
+  for (var i = 0; i < list.length; i++) {
     if (predicate(list[i])) { return list[i]; }
   }
 
diff --git a/packages/ember-template-compiler/lib/plugins/transform-input-on-to-onEvent.js b/packages/ember-template-compiler/lib/plugins/transform-input-on-to-onEvent.js
index 9d7d952d66c..81d4ae20446 100644
--- a/packages/ember-template-compiler/lib/plugins/transform-input-on-to-onEvent.js
+++ b/packages/ember-template-compiler/lib/plugins/transform-input-on-to-onEvent.js
@@ -113,7 +113,7 @@ TransformInputOnToOnEvent.prototype.validate = function TransformWithAsToHash_va
 };
 
 function hashPairForKey(hash, key) {
-  for (let i = 0, l = hash.pairs.length; i < l; i++) {
+  for (let i = 0; i < hash.pairs.length; i++) {
     let pair = hash.pairs[i];
     if (pair.key === key) {
       return pair;
@@ -125,7 +125,7 @@ function hashPairForKey(hash, key) {
 
 function removeFromHash(hash, pairToRemove) {
   var newPairs = [];
-  for (let i = 0, l = hash.pairs.length; i < l; i++) {
+  for (let i = 0; i < hash.pairs.length; i++) {
     let pair = hash.pairs[i];
 
     if (pair !== pairToRemove) {
diff --git a/packages/ember-template-compiler/lib/plugins/transform-item-class.js b/packages/ember-template-compiler/lib/plugins/transform-item-class.js
index 18a91e7ec71..96c2483009d 100644
--- a/packages/ember-template-compiler/lib/plugins/transform-item-class.js
+++ b/packages/ember-template-compiler/lib/plugins/transform-item-class.js
@@ -35,7 +35,7 @@ function validate(node) {
 }
 
 function each(list, callback) {
-  for (var i = 0, l = list.length; i < l; i++) {
+  for (var i = 0; i < list.length; i++) {
     callback(list[i]);
   }
 }
diff --git a/packages/ember-template-compiler/lib/plugins/transform-old-binding-syntax.js b/packages/ember-template-compiler/lib/plugins/transform-old-binding-syntax.js
index ba51841f61d..f9767aa8971 100644
--- a/packages/ember-template-compiler/lib/plugins/transform-old-binding-syntax.js
+++ b/packages/ember-template-compiler/lib/plugins/transform-old-binding-syntax.js
@@ -48,7 +48,7 @@ function validate(node) {
 }
 
 function each(list, callback) {
-  for (var i = 0, l = list.length; i < l; i++) {
+  for (var i = 0; i < list.length; i++) {
     callback(list[i]);
   }
 }
diff --git a/packages/ember-template-compiler/lib/plugins/transform-old-class-binding-syntax.js b/packages/ember-template-compiler/lib/plugins/transform-old-class-binding-syntax.js
index 0c49974a295..9e4ebef9d5d 100644
--- a/packages/ember-template-compiler/lib/plugins/transform-old-class-binding-syntax.js
+++ b/packages/ember-template-compiler/lib/plugins/transform-old-class-binding-syntax.js
@@ -63,7 +63,7 @@ TransformOldClassBindingSyntax.prototype.transform = function TransformOldClassB
 };
 
 function buildSexprs(microsyntax, sexprs, b) {
-  for (var i = 0, l = microsyntax.length; i < l; i++) {
+  for (var i = 0; i < microsyntax.length; i++) {
     let [propName, activeClass, inactiveClass] = microsyntax[i];
     let sexpr;
 
@@ -107,7 +107,7 @@ function validate(node) {
 }
 
 function each(list, callback) {
-  for (var i = 0, l = list.length; i < l; i++) {
+  for (var i = 0; i < list.length; i++) {
     callback(list[i], i);
   }
 }
@@ -115,7 +115,7 @@ function each(list, callback) {
 function parseMicrosyntax(string) {
   var segments = string.split(' ');
 
-  for (var i = 0, l = segments.length; i < l; i++) {
+  for (var i = 0; i < segments.length; i++) {
     segments[i] = segments[i].split(':');
   }
 
diff --git a/packages/ember-template-compiler/lib/plugins/transform-top-level-components.js b/packages/ember-template-compiler/lib/plugins/transform-top-level-components.js
index d1ec98a5bec..eeecc7c55c5 100644
--- a/packages/ember-template-compiler/lib/plugins/transform-top-level-components.js
+++ b/packages/ember-template-compiler/lib/plugins/transform-top-level-components.js
@@ -41,7 +41,7 @@ function hasSingleComponentNode(program, componentCallback, elementCallback) {
   let lastIndex;
   let nodeCount = 0;
 
-  for (let i = 0, l = body.length; i < l; i++) {
+  for (let i = 0; i < body.length; i++) {
     let curr = body[i];
 
     // text node with whitespace only
diff --git a/packages/ember-template-compiler/lib/system/compile_options.js b/packages/ember-template-compiler/lib/system/compile_options.js
index a7b2141f696..5bb1ad40e8c 100644
--- a/packages/ember-template-compiler/lib/system/compile_options.js
+++ b/packages/ember-template-compiler/lib/system/compile_options.js
@@ -55,7 +55,7 @@ function fragmentReason(program) {
 
   let problems = {};
 
-  for (let i = 0, l = body.length; i < l; i++) {
+  for (let i = 0; i < body.length; i++) {
     let curr = body[i];
 
     // text node with whitespace only
diff --git a/packages/ember-template-compiler/tests/plugins/transform-each-into-collection-test.js b/packages/ember-template-compiler/tests/plugins/transform-each-into-collection-test.js
index e14ba782700..12921423ca3 100644
--- a/packages/ember-template-compiler/tests/plugins/transform-each-into-collection-test.js
+++ b/packages/ember-template-compiler/tests/plugins/transform-each-into-collection-test.js
@@ -38,7 +38,7 @@ function testNonBlockForm(attr) {
   });
 }
 
-for (let i = 0, l = deprecatedAttrs.length; i < l; i++) {
+for (let i = 0; i < deprecatedAttrs.length; i++) {
   let attr = deprecatedAttrs[i];
 
   testBlockForm(attr);
diff --git a/packages/ember-testing/lib/test.js b/packages/ember-testing/lib/test.js
index 2d6bfe54996..68a13c2bf2a 100644
--- a/packages/ember-testing/lib/test.js
+++ b/packages/ember-testing/lib/test.js
@@ -437,7 +437,7 @@ EmberApplication.reopen({
       protoWrap(Test.Promise.prototype, name, helper(this, name), helpers[name].meta.wait);
     }
 
-    for (var i = 0, l = injectHelpersCallbacks.length; i < l; i++) {
+    for (var i = 0; i < injectHelpersCallbacks.length; i++) {
       injectHelpersCallbacks[i](this);
     }
   },
diff --git a/packages/ember-views/lib/mixins/view_support.js b/packages/ember-views/lib/mixins/view_support.js
index 7d87703568d..71dca38e201 100644
--- a/packages/ember-views/lib/mixins/view_support.js
+++ b/packages/ember-views/lib/mixins/view_support.js
@@ -225,10 +225,9 @@ export default Mixin.create({
 
     if (!childViews) { return this; }
 
-    var len = childViews.length;
     var view, idx;
 
-    for (idx = 0; idx < len; idx++) {
+    for (idx = 0; idx < childViews.length; idx++) {
       view = childViews[idx];
       callback(view);
     }
diff --git a/packages/ember-views/lib/system/build-component-template.js b/packages/ember-views/lib/system/build-component-template.js
index c4ededfe487..82e5bb8edc6 100644
--- a/packages/ember-views/lib/system/build-component-template.js
+++ b/packages/ember-views/lib/system/build-component-template.js
@@ -158,7 +158,7 @@ function normalizeComponentAttributes(component, isAngleBracket, attrs) {
   var normalized = {};
   var attributeBindings = component.attributeBindings;
   var streamBasePath = component.isComponent ? '' : 'view.';
-  var i, l;
+  var i;
 
   if (attrs.id && getValue(attrs.id)) {
     // Do not allow binding to the `id`
@@ -169,7 +169,7 @@ function normalizeComponentAttributes(component, isAngleBracket, attrs) {
   }
 
   if (attributeBindings) {
-    for (i = 0, l = attributeBindings.length; i < l; i++) {
+    for (i = 0; i < attributeBindings.length; i++) {
       var attr = attributeBindings[i];
       var colonIndex = attr.indexOf(':');
 
@@ -232,7 +232,7 @@ function normalizeComponentAttributes(component, isAngleBracket, attrs) {
 }
 
 function normalizeClass(component, attrs, streamBasePath) {
-  var i, l;
+  var i;
   var normalizedClass = [];
   var classNames = get(component, 'classNames');
   var classNameBindings = get(component, 'classNameBindings');
@@ -250,7 +250,7 @@ function normalizeClass(component, attrs, streamBasePath) {
   }
 
   if (classNames) {
-    for (i = 0, l = classNames.length; i < l; i++) {
+    for (i = 0; i < classNames.length; i++) {
       normalizedClass.push(classNames[i]);
     }
   }
@@ -265,9 +265,9 @@ function normalizeClass(component, attrs, streamBasePath) {
 }
 
 function normalizeClasses(classes, output, streamBasePath) {
-  var i, l;
+  var i;
 
-  for (i = 0, l = classes.length; i < l; i++) {
+  for (i = 0; i < classes.length; i++) {
     var className = classes[i];
     assert('classNameBindings must not have spaces in them. Multiple class name bindings can be provided as elements of an array, e.g. [\'foo\', \':bar\']', className.indexOf(' ') === -1);
 
diff --git a/packages/ember-views/lib/system/event_dispatcher.js b/packages/ember-views/lib/system/event_dispatcher.js
index 955f810729b..4a55f72d0b8 100644
--- a/packages/ember-views/lib/system/event_dispatcher.js
+++ b/packages/ember-views/lib/system/event_dispatcher.js
@@ -229,7 +229,7 @@ export default EmberObject.extend({
         return;
       }
 
-      for (let index = 0, length = actions.length; index < length; index++) {
+      for (let index = 0; index < actions.length; index++) {
         let action = actions[index];
 
         if (action && action.eventName === eventName) {
diff --git a/packages/ember-views/lib/views/collection_view.js b/packages/ember-views/lib/views/collection_view.js
index 7308ea7b6ea..643946329a2 100644
--- a/packages/ember-views/lib/views/collection_view.js
+++ b/packages/ember-views/lib/views/collection_view.js
@@ -364,7 +364,7 @@ var CollectionView = ContainerView.extend(EmptyViewSupport, {
     this._itemViewProps = itemProps;
     var childViews = get(this, 'childViews');
 
-    for (var i = 0, l = childViews.length; i < l; i++) {
+    for (var i = 0; i < childViews.length; i++) {
       childViews[i].setProperties(itemProps);
     }
 
diff --git a/packages/ember-views/lib/views/container_view.js b/packages/ember-views/lib/views/container_view.js
index 8352500a380..68ede6d76b7 100644
--- a/packages/ember-views/lib/views/container_view.js
+++ b/packages/ember-views/lib/views/container_view.js
@@ -249,7 +249,7 @@ var ContainerView = View.extend(MutableArray, {
     let childViews = get(this, 'childViews');
 
     assert('You can\'t add a child to a container - the child is already a child of another view', () => {
-      for (let i = 0, l = addedViews.length; i < l; i++) {
+      for (let i = 0; i < addedViews.length; i++) {
         let item = addedViews[i];
         if (item.parentView && item.parentView !== this) { return false; }
       }
diff --git a/packages/ember-views/lib/views/core_view.js b/packages/ember-views/lib/views/core_view.js
index efc14f343e6..f7b9de2f899 100644
--- a/packages/ember-views/lib/views/core_view.js
+++ b/packages/ember-views/lib/views/core_view.js
@@ -93,9 +93,8 @@ const CoreView = EmberObject.extend(Evented, ActionHandler, {
     var name = arguments[0];
     var method = this[name];
     if (method) {
-      var length = arguments.length;
-      var args = new Array(length - 1);
-      for (var i = 1; i < length; i++) {
+      var args = new Array(arguments.length - 1);
+      for (var i = 1; i < arguments.length; i++) {
         args[i - 1] = arguments[i];
       }
       return method.apply(this, args);
diff --git a/packages/loader/lib/index.js b/packages/loader/lib/index.js
index 3158e7b8762..6557d80c9ea 100644
--- a/packages/loader/lib/index.js
+++ b/packages/loader/lib/index.js
@@ -71,10 +71,9 @@ var mainContext = this;
 
       var deps = mod.deps;
       var callback = mod.callback;
-      var length = deps.length;
-      var reified = new Array(length);;
+      var reified = new Array(deps.length);
 
-      for (var i = 0; i < length; i++) {
+      for (var i = 0; i < deps.length; i++) {
         if (deps[i] === 'exports') {
           reified[i] = exports;
         } else if (deps[i] === 'require') {