janesconference janesconference - 4 months ago 9
AngularJS Question

AngularJS: ng-repeat list is not updated when a model element is spliced from the model array

I have two controllers and share data between them with an app.factory function.

The first controller adds a widget in the model array (pluginsDisplayed) when a link is clicked. The widget is pushed into the array and this change is reflected into the view (that uses ng-repeat to show the array content):

<div ng-repeat="pluginD in pluginsDisplayed">
<div k2plugin pluginname="{{pluginD.name}}" pluginid="{{pluginD.id}}"></div>
</div>


The widget is built upon three directives, k2plugin, remove and resize. The remove directive adds a span to the template of the k2plugin directive. When said span is clicked, the right element into the shared array is deleted with
Array.splice()
. The shared array is correctly updated, but the change is not reflected in the view. However, when another element is added, after the remove, the view is refreshed correctly and the previously-deleted element is not shown.

What am I getting wrong? Could you explain me why this doesn't work?
Is there a better way to do what I'm trying to do with AngularJS?

This is my index.html:

<!doctype html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.5/angular.min.js">
</script>
<script src="main.js"></script>
</head>
<body>
<div ng-app="livePlugins">
<div ng-controller="pluginlistctrl">
<span>Add one of {{pluginList.length}} plugins</span>
<li ng-repeat="plugin in pluginList">
<span><a href="" ng-click="add()">{{plugin.name}}</a></span>
</li>
</div>
<div ng-controller="k2ctrl">
<div ng-repeat="pluginD in pluginsDisplayed">
<div k2plugin pluginname="{{pluginD.name}}" pluginid="{{pluginD.id}}"></div>
</div>
</div>
</div>
</body>
</html>


This is my main.js:

var app = angular.module ("livePlugins",[]);

app.factory('Data', function () {
return {pluginsDisplayed: []};
});

app.controller ("pluginlistctrl", function ($scope, Data) {
$scope.pluginList = [{name: "plugin1"}, {name:"plugin2"}, {name:"plugin3"}];
$scope.add = function () {
console.log ("Called add on", this.plugin.name, this.pluginList);
var newPlugin = {};
newPlugin.id = this.plugin.name + '_' + (new Date()).getTime();
newPlugin.name = this.plugin.name;
Data.pluginsDisplayed.push (newPlugin);
}
})

app.controller ("k2ctrl", function ($scope, Data) {
$scope.pluginsDisplayed = Data.pluginsDisplayed;

$scope.remove = function (element) {
console.log ("Called remove on ", this.pluginid, element);

var len = $scope.pluginsDisplayed.length;
var index = -1;

// Find the element in the array
for (var i = 0; i < len; i += 1) {
if ($scope.pluginsDisplayed[i].id === this.pluginid) {
index = i;
break;
}
}

// Remove the element
if (index !== -1) {
console.log ("removing the element from the array, index: ", index);
$scope.pluginsDisplayed.splice(index,1);
}

}
$scope.resize = function () {
console.log ("Called resize on ", this.pluginid);
}
})

app.directive("k2plugin", function () {
return {
restrict: "A",
scope: true,
link: function (scope, elements, attrs) {
console.log ("creating plugin");

// This won't work immediately. Attribute pluginname will be undefined
// as soon as this is called.
scope.pluginname = "Loading...";
scope.pluginid = attrs.pluginid;

// Observe changes to interpolated attribute
attrs.$observe('pluginname', function(value) {
console.log('pluginname has changed value to ' + value);
scope.pluginname = attrs.pluginname;
});

// Observe changes to interpolated attribute
attrs.$observe('pluginid', function(value) {
console.log('pluginid has changed value to ' + value);
scope.pluginid = attrs.pluginid;
});
},
template: "<div>{{pluginname}} <span resize>_</span> <span remove>X</span>" +
"<div>Plugin DIV</div>" +
"</div>",
replace: true
};
});

app.directive("remove", function () {
return function (scope, element, attrs) {
element.bind ("mousedown", function () {
scope.remove(element);
})
};

});

app.directive("resize", function () {
return function (scope, element, attrs) {
element.bind ("mousedown", function () {
scope.resize(element);
})
};
});

Answer

Whenever you do some form of operation outside of AngularJS, such as doing an Ajax call with jQuery, or binding an event to an element like you have here you need to let AngularJS know to update itself. Here is the code change you need to do:

app.directive("remove", function () {
    return function (scope, element, attrs) {
        element.bind ("mousedown", function () {
            scope.remove(element);
            scope.$apply();
        })
    };

});

app.directive("resize", function () {
    return function (scope, element, attrs) {
        element.bind ("mousedown", function () {
            scope.resize(element);
            scope.$apply();
        })
    };
});

Here is the documentation on it: https://docs.angularjs.org/api/ng/type/$rootScope.Scope#$apply

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