How to remove elements/nodes from angular.js array

2019-01-16 02:44发布

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?

12条回答
甜甜的少女心
2楼-- · 2019-01-16 02:44

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="angular.js@1.1.5" 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);
  }
}
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疯言疯语
3楼-- · 2019-01-16 02:44

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"

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混吃等死
4楼-- · 2019-01-16 02:47

My solution to this (which hasn't caused any performance issues):

  1. 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

  1. 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.

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别忘想泡老子
5楼-- · 2019-01-16 02:48

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);
    }
});
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该账号已被封号
6楼-- · 2019-01-16 02:49

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="angular.js@1.1.5" 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);
  }
}
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劳资没心,怎么记你
7楼-- · 2019-01-16 02:52

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);
    }
}
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