(simple plunkr demo here)
SUMMARY:
There is a leak using ng-repeat after the 2nd wave iterating over an 'array' of custom objects like this :
<div ng-repeat="d_sampleObject in mySampleObjects">
{{d_sampleObject.description}}
</div>
Memory profile reveals an extra 'd_sampleObject' left over and not de-referenced. More details (via a controller and an injected service) below. A simple demonstration also in the provided plunkr link. Any thoughts and help greatly appreciated in advance!
NOTE: 'mySampleObjects' is an array of the following instances:
ml.MySampleObject = function (id) {
this.id = id;
this.description = 'this is object #:' + ' '+id;
}
DETAILS:
I have a custom object model that reflects the business domain objects that we utilize in our AngularJS app. I have found that when I pass an instance of one of my custom objects to ng-repeat, a reference is kept to it (I think by Angular) and memory is not freed. This happens on the second 'wave' (click on 'refresh') of the ng-repeat as it iterates, again, over its array of objects. This leak is exposed in my Profile tests (in Chrome) . Here is a short example in plunkr. Click on 'refresh' button once (or more) to see the extra 'd_sampleObject' object instance that is leaked (in Chrome Profile Inspection). Note, the 'd_sampleObject' name is only used when passed to ng-repeat. I have included screenshots of the extra object instance ('d_sampleObject') that is being leaked further below. Why is there a leak and how can it be avoided?
(Note, I have found if I don't iterate over my object collection (JS array) thru an object but rather thru a primitive index ('integer'), there is no leak. The leak seems to only happen when I use an object reference as a result of ng-repeat iterations)
SIMPLE HTML:
<!DOCTYPE html>
<html ng-app="memoryleak">
<head>
<meta charset="utf-8" />
<title>Memory Leak Test</title>
<script>document.write('<base href="' + document.location + '" />');</script>
<script data-require="angular.js@1.3.x" src="https://code.angularjs.org/1.3.13/angular.min.js" data-semver="1.3.13"></script>
<script src="app.js"></script>
<script src="dataservice.js"></script>
</head>
<body ng-controller="MainCtrl">
<div ng-repeat="d_sampleObject in mySampleObjects">
{{d_sampleObject.description}}
</div>
<br>
<button ng-click="redo()">Number of refreshes: {{numRedos}}!</button>
</body>
</html>
SIMPLE APP.JS
(function(ml) {
var app = angular.module('memoryleak',['servicemodule']);
app.controller('MainCtrl', ['$scope', 'dataservice', function($scope, dataservice) {
$scope.redo = function () {
$scope.numRedos++;
$scope.mySampleObjects = dataservice.myObjectCollection;
dataservice.redo();
}
$scope.redo();
}]);
}(window.MEMLEAK = window.MEMLEAK || {}));
SIMPLE dataservice.js
(function(ml) {
'use strict';
var serviceModule = angular.module('servicemodule',[]);
serviceModule.factory('dataservice', ['$rootScope', '$http',
function ($rootScope, $http) {
this.myObjectCollection = [];
this.redo = function () {
this.numRedos++;
// that.myObjectCollection = [];
this.myObjectCollection.length = 0;
for (var i = 0; i < 10; i++) {
var sampleObject = new ml.MySampleObject(i);
that.myObjectCollection.push(sampleObject);
}
sampleObject=null;
}
ml.MySampleObject = function (id) {
this.id = id;
this.description = 'this is object #:' + ' '+id;
}
return this; //return the entire service to make methods accessible to dependents
}]);
}(window.MEMLEAK = window.MEMLEAK || {}));
SCREENSHOT 1: (FIRST PAGE LOAD--there are 10 'mySampleObjects' created)
SCREENSHOT 2: (CLICKED ON REFRESH--there is an 11th mySampleObject created/leaked with a reference to the instance name of 'd_sampleObject' passed to ng-repeat.)
There is acknowledgement by the AngularJS folks that this is indeed a bug in the framework. A fix and pull request has been posted.
I have also asked what the timeframe is for a formal fix.
来源：https://stackoverflow.com/questions/28683992/angularjs-memory-leak-with-ng-repeat-using-custom-objects-w-simple-plunkr