How do I bind to list of checkbox values with AngularJS?

Question

I have a few checkboxes:

Answer 1

In the HTML (supposing that the checkboxes are in the first column of every row in a table).

<tr ng-repeat="item in fruits">
    <td><input type="checkbox" ng-model="item.checked" ng-click="getChecked(item)"></td>
    <td ng-bind="fruit.name"></td>
    <td ng-bind="fruit.color"></td>
    ...
</tr>

In the controllers.js file:

// The data initialization part...
$scope.fruits = [
    {
      name: ....,
      color:....
    },
    {
      name: ....,
      color:....
    }
     ...
    ];

// The checked or not data is stored in the object array elements themselves
$scope.fruits.forEach(function(item){
    item.checked = false;
});

// The array to store checked fruit items
$scope.checkedItems = [];

// Every click on any checkbox will trigger the filter to find checked items
$scope.getChecked = function(item){
    $scope.checkedItems = $filter("filter")($scope.fruits,{checked:true});
};

Answer 2

I think the easiest workaround would be to use 'select' with 'multiple' specified:

<select ng-model="selectedfruit" multiple ng-options="v for v in fruit"></select>

Otherwise, I think you'll have to process the list to construct the list (by $watch()ing the model array bind with checkboxes).

Answer 3

Based on my other post here, I have made a reusable directive.

Check out the GitHub repository

(function () {
   
   angular
      .module("checkbox-select", [])
      .directive("checkboxModel", ["$compile", function ($compile) {
         return {
            restrict: "A",
            link: function (scope, ele, attrs) {
               // Defining updateSelection function on the parent scope
               if (!scope.$parent.updateSelections) {
                  // Using splice and push methods to make use of 
                  // the same "selections" object passed by reference to the 
                  // addOrRemove function as using "selections = []" 
                  // creates a new object within the scope of the 
                  // function which doesn't help in two way binding.
                  scope.$parent.updateSelections = function (selectedItems, item, isMultiple) {
                     var itemIndex = selectedItems.indexOf(item)
                     var isPresent = (itemIndex > -1)
                     if (isMultiple) {
                        if (isPresent) {
                           selectedItems.splice(itemIndex, 1)
                        } else {
                           selectedItems.push(item)
                        }
                     } else {
                        if (isPresent) {
                           selectedItems.splice(0, 1)
                        } else {
                           selectedItems.splice(0, 1, item)
                        }
                     }
                  }   
               }
               
               // Adding or removing attributes
               ele.attr("ng-checked", attrs.checkboxModel + ".indexOf(" + attrs.checkboxValue + ") > -1")
               var multiple = attrs.multiple ? "true" : "false"
               ele.attr("ng-click", "updateSelections(" + [attrs.checkboxModel, attrs.checkboxValue, multiple].join(",") + ")")
               
               // Removing the checkbox-model attribute, 
               // it will avoid recompiling the element infinitly
               ele.removeAttr("checkbox-model")
               ele.removeAttr("checkbox-value")
               ele.removeAttr("multiple")
               
               $compile(ele)(scope)
            }
         }
      }])
   
      // Defining app and controller
      angular
      .module("APP", ["checkbox-select"])
      .controller("demoCtrl", ["$scope", function ($scope) {
         var dc = this
         dc.list = [
            "selection1",
            "selection2",
            "selection3"
         ]
         
         // Define the selections containers here
         dc.multipleSelections = []
         dc.individualSelections = []
      }])
   
})()

label {
  display: block;  
}

<!DOCTYPE html>
<html>

   <head>
      <link rel="stylesheet" href="style.css" />
      
   </head>
   
   <body ng-app="APP" ng-controller="demoCtrl as dc">
      <h1>checkbox-select demo</h1>
      
      <h4>Multiple Selections</h4>
      <label ng-repeat="thing in dc.list">
         <input type="checkbox" checkbox-model="dc.multipleSelections" checkbox-value="thing" multiple>
         {{thing}}
      </label>
      <p>dc.multipleSelecitons:- {{dc.multipleSelections}}</p>
      
      <h4>Individual Selections</h4>
      <label ng-repeat="thing in dc.list">
         <input type="checkbox" checkbox-model="dc.individualSelections" checkbox-value="thing">
         {{thing}}
      </label>
      <p>dc.individualSelecitons:- {{dc.individualSelections}}</p>
      
      <script data-require="jquery@3.0.0" data-semver="3.0.0" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0/jquery.js"></script>
      <script data-require="angular.js@1.5.6" data-semver="1.5.6" src="https://code.angularjs.org/1.5.6/angular.min.js"></script>
      <script src="script.js"></script>
   </body>

</html>

Answer 4

Since you accepted an answer in which a list was not used, I'll assume the answer to my comment question is "No, it doesn't have to be a list". I also had the impression that maybe you were rending the HTML server side, since "checked" is present in your sample HTML (this would not be needed if ng-model were used to model your checkboxes).

Anyway, here's what I had in mind when I asked the question, also assuming you were generating the HTML server-side:

<div ng-controller="MyCtrl" 
 ng-init="checkboxes = {apple: true, orange: false, pear: true, naartjie: false}">
    <input type="checkbox" ng-model="checkboxes.apple">apple
    <input type="checkbox" ng-model="checkboxes.orange">orange
    <input type="checkbox" ng-model="checkboxes.pear">pear
    <input type="checkbox" ng-model="checkboxes.naartjie">naartjie
    <br>{{checkboxes}}
</div>

ng-init allows server-side generated HTML to initially set certain checkboxes.

Fiddle.

Answer 5

There is a way to work on the array directly and use ng-model at the same time through ng-model-options="{ getterSetter: true }".

The trick is to use a getter/setter function in your ng-model. This way you can use an array as your real model and "fake" the booleans in the input's model:

<label ng-repeat="fruitName in ['apple', 'orange', 'pear', 'naartjie']">
  <input
    type="checkbox"
    ng-model="fruitsGetterSetterGenerator(fruitName)"
    ng-model-options="{ getterSetter: true }"
  > {{fruitName}}
</label>

$scope.fruits = ['apple', 'pear']; // pre checked

$scope.fruitsGetterSetterGenerator = function(fruitName){
    return function myGetterSetter(nowHasFruit){
        if (nowHasFruit !== undefined){

            // Setter
            fruitIndex = $scope.fruits.indexOf(fruit);
            didHaveFruit = (fruitIndex !== -1);
            mustAdd = (!didHaveFruit && nowHasFruit);
            mustDel = (didHaveFruit && !nowHasFruit);
            if (mustAdd){
                $scope.fruits.push(fruit);
            }
            if (mustDel){
                $scope.fruits.splice(fruitIndex, 1);
            }
        }
        else {
            // Getter
            return $scope.user.fruits.indexOf(fruit) !== -1;
        }
    }
}

CAVEAT You shouldn't use this method if your arrays are big as myGetterSetter will be called a lot of times.

For more on that, see https://docs.angularjs.org/api/ng/directive/ngModelOptions.