How to remove elements/nodes from angular.js array
AngularjsScopeAngularjs Ng-RepeatAngularjs Problem Overview
I am trying to remove elements from the array $scope.items so that items are removed in the view ng-repeat="item in items"
Just for demonstrative purposes here is some code:
for(i=0;i<$scope.items.length;i++){
if($scope.items[i].name == 'ted'){
$scope.items.shift();
}
}
I want to remove the 1st element from the view if there is the name ted right? It works fine, but the view reloads all the elements. Because all the array keys have shifted. This is creating unnecessary lag in the mobile app I am creating..
Anyone have an solutions to this problem?
Angularjs Solutions
Solution 1 - Angularjs
There is no rocket science in deleting items from array. To delete items from any array you need to use splice: $scope.items.splice(index, 1);. Here is an example:
HTML
<!DOCTYPE html>
<html data-ng-app="demo">
<head>
<script data-require="[email protected]" data-semver="1.1.5" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.1.5/angular.js"></script>
<link rel="stylesheet" href="style.css" />
<script src="script.js"></script>
</head>
<body>
<div data-ng-controller="DemoController">
<ul>
<li data-ng-repeat="item in items">
{{item}}
<button data-ng-click="removeItem($index)">Remove</button>
</li>
</ul>
<input data-ng-model="newItem"><button data-ng-click="addItem(newItem)">Add</button>
</div>
</body>
</html>
JavaScript
"use strict";
var demo = angular.module("demo", []);
function DemoController($scope){
$scope.items = [
"potatoes",
"tomatoes",
"flour",
"sugar",
"salt"
];
$scope.addItem = function(item){
$scope.items.push(item);
$scope.newItem = null;
}
$scope.removeItem = function(index){
$scope.items.splice(index, 1);
}
}
Solution 2 - Angularjs
For anyone returning to this question. The correct "Angular Way" to remove items from an array is with $filter. Just inject $filter into your controller and do the following:
$scope.items = $filter('filter')($scope.items, {name: '!ted'})
You don't need to load any additional libraries or resort to Javascript primitives.
Solution 3 - Angularjs
You can use plain javascript - Array.prototype.filter()
$scope.items = $scope.items.filter(function(item) {
return item.name !== 'ted';
});
Solution 4 - Angularjs
Because when you do shift() on an array, it changes the length of the array. So the for loop will be messed up. You can loop through from end to front to avoid this problem.
Btw, I assume you try to remove the element at the position i rather than the first element of the array. ($scope.items.shift(); in your code will remove the first element of the array)
for(var i = $scope.items.length - 1; i >= 0; i--){
if($scope.items[i].name == 'ted'){
$scope.items.splice(i,1);
}
}
Solution 5 - Angularjs
Here is filter with Underscore library might help you, we remove item with name "ted"
$scope.items = _.filter($scope.items, function(item) {
return !(item.name == 'ted');
});
Solution 6 - Angularjs
I liked the solution provided by @madhead
However the problem I had is that it wouldn't work for a sorted list so instead of passing the index to the delete function I passed the item and then got the index via indexof
e.g.:
var index = $scope.items.indexOf(item);
$scope.items.splice(index, 1);
An updated version of madheads example is below: link to example
HTML
<!DOCTYPE html>
<html data-ng-app="demo">
<head>
<script data-require="[email protected]" data-semver="1.1.5" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.1.5/angular.js"></script>
<link rel="stylesheet" href="style.css" />
<script src="script.js"></script>
</head>
<body>
<div data-ng-controller="DemoController">
<ul>
<li data-ng-repeat="item in items|orderBy:'toString()'">
{{item}}
<button data-ng-click="removeItem(item)">Remove</button>
</li>
</ul>
<input data-ng-model="newItem"><button data-ng-click="addItem(newItem)">Add</button>
</div>
</body>
</html>
JavaScript
"use strict";
var demo = angular.module("demo", []);
function DemoController($scope){
$scope.items = [
"potatoes",
"tomatoes",
"flour",
"sugar",
"salt"
];
$scope.addItem = function(item){
$scope.items.push(item);
$scope.newItem = null;
}
$scope.removeItem = function(item){
var index = $scope.items.indexOf(item);
$scope.items.splice(index, 1);
}
}
Solution 7 - Angularjs
Just a slight expansion on the 'angular' solution. I wanted to exclude an item based on it's numeric id, so the ! approach doesn't work. The more general solution which should work for { name: 'ted' } or { id: 42 } is:
mycollection = $filter('filter')(myCollection, { id: theId }, function (obj, test) {
return obj !== test; });
Solution 8 - Angularjs
My solution to this (which hasn't caused any performance issues):
- Extend the array object with a method remove (i'm sure you will need it more than just one time):
> Array.prototype.remove = function(from, to) { > var rest = this.slice((to || from) + 1 || this.length); > this.length = from < 0 ? this.length + from : from; > return this.push.apply(this, rest); > };
I'm using it in all of my projects and credits go to John Resig John Resig's Site
- Using forEach and a basic check:
> $scope.items.forEach(function(element, index, array){ > if(element.name === 'ted'){ > $scope.items.remove(index); > } > });
At the end the $digest will be fired in angularjs and my UI is updated immediately without any recognizable lag.
Solution 9 - Angularjs
If you have any function associated to list ,when you make the splice function, the association is deleted too. My solution:
$scope.remove = function() {
var oldList = $scope.items;
$scope.items = [];
angular.forEach(oldList, function(x) {
if (! x.done) $scope.items.push( { [ DATA OF EACH ITEM USING oldList(x) ] });
});
};
The list param is named items. The param x.done indicate if the item will be deleted. Hope help you. Greetings.
Solution 10 - Angularjs
Using the indexOf function was not cutting it on my collection of REST resources.
I had to create a function that retrieves the array index of a resource sitting in a collection of resources:
factory.getResourceIndex = function(resources, resource) {
var index = -1;
for (var i = 0; i < resources.length; i++) {
if (resources[i].id == resource.id) {
index = i;
}
}
return index;
}
$scope.unassignedTeams.splice(CommonService.getResourceIndex($scope.unassignedTeams, data), 1);
Solution 11 - Angularjs
My solution was quite straight forward
app.controller('TaskController', function($scope) {
$scope.items = tasks;
$scope.addTask = function(task) {
task.created = Date.now();
$scope.items.push(task);
console.log($scope.items);
};
$scope.removeItem = function(item) {
// item is the index value which is obtained using $index in ng-repeat
$scope.items.splice(item, 1);
}
});
Solution 12 - Angularjs
My items have unique id's. I am deleting one by filtering the model with angulars $filter service:
var myModel = [{id:12345, ...},{},{},...,{}];
...
// working within the item
function doSthWithItem(item){
...
myModel = $filter('filter')(myModel, function(value, index)
{return value.id !== item.id;}
);
}
As id you could also use the $$hashKey property of your model items: $$hashKey:"object:91"