Don't cache length property in for loops

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
 }
 

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);
       }

packages/container/lib/container.js

@@ -226,15 +226,15 @@ 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]);
       }
     }
 
     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];
 

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)) {

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(''));

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)) {

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) {

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]();
     }
   }

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]);
       }

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]);
   }
 

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();
     }
 

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]);
   }
 

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];

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');
   }

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;
   }
 

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];
     }

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);

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);
   }
 

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);

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]);

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;

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;
     }

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);

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];
   }