Communication within the intermediate scopes between the directive and the controller

Question

Communication within the intermediate scopes between the directive and the controller

In my AngularJS HTML code, I have the following:

<div ng-controller="myController">
    <div ng-grid="myGrid"></div>
</div>

The ngGrid component creates a table-like structure with a viewport, rows, and cells, each having their own scope. Within one of these cells, I created a custom directive called <range>, similar to the HTML5 <input type="number"> tag. The scope chain now looks like this:

myController -> ngGrid -> ngViewport -> ngRow -> ngCell -> range

My goal is to retrieve the value of the <input> within the <range> directive and pass it back to

myController</code in a reusable way, without explicitly calling <code>scope.$parent.$parent.$parent.$parent.$parent

. I've tried requiring the controller within the directive, as suggested in this post, but it didn't work. I also attempted expression binding from this egghead.io video without success. I'm stuck on how to proceed from here.

javascript angularjs angularjs-directive

Answer 1

Answer №1

When the <input> looks like this (remember ng-model is at the top level):

<input type="number" ng-model="name" />

Modify the model so that it resides in a higher level:

<input type="number" ng-model="data.name" />

Answer 2

When the <input> looks like this (remember ng-model is at the top level):

<input type="number" ng-model="name" />

Modify the model so that it resides in a higher level:

<input type="number" ng-model="data.name" />

Answer 3

Answer №2

The ability to use the parent controller's function here is due to setting the 'item' model equal to the parent's 'item' within the directive's scope. To access a function on myController in your range directive, it is necessary to have a model set equally between each scope layer from myController to range.

An alternative solution could be to utilize Angular's pubsub system. If there is a specific event triggering code in the range directive that indicates you want to capture that value in myController (such as onBlur event), you can emit the value up the scope hierarchy and listen for the emitted event in myController to capture the value.

Emitting an event from range directive and passing its value:

scope.$emit("CAPTURE_VALUE", scope.inputModel);

Listening for the event in myController and capturing the passed value:

$scope.$on("CAPTURE_VALUE", function(event, passedValue){
    $scope.rangeValue = passedValue;
};

Now, as long as the range directive is within a child scope of myController, you should be able to retrieve the input value regardless of how deep it is.

Answer 4

The ability to use the parent controller's function here is due to setting the 'item' model equal to the parent's 'item' within the directive's scope. To access a function on myController in your range directive, it is necessary to have a model set equally between each scope layer from myController to range.

An alternative solution could be to utilize Angular's pubsub system. If there is a specific event triggering code in the range directive that indicates you want to capture that value in myController (such as onBlur event), you can emit the value up the scope hierarchy and listen for the emitted event in myController to capture the value.

Emitting an event from range directive and passing its value:

scope.$emit("CAPTURE_VALUE", scope.inputModel);

Listening for the event in myController and capturing the passed value:

$scope.$on("CAPTURE_VALUE", function(event, passedValue){
    $scope.rangeValue = passedValue;
};

Now, as long as the range directive is within a child scope of myController, you should be able to retrieve the input value regardless of how deep it is.

Answer 5

Answer №3

In order to avoid calling the parent chain, you can simply utilize scope.$parent. Since scopes inherit from their parent scope in a prototypical manner, any non-value type can be safely accessed and modified. For a deeper understanding of how scope inheritance functions, refer to this informative response.

Below is the essential code for your reference. I have demonstrated the communication example through two methods; one involves dependency injection of a common model, while the other makes use of the parent scope.

View the working Plunker

var app = angular.module('myApp', ['ngGrid']);

app.factory('rangeValues', function() {
    return [];
});

app.controller('MyCtrl', function($scope, rangeValues) {
    $scope.factoryRangeValues = rangeValues;
    $scope.parentScopeRangeValues = [];
    $scope.myData = [
        {name: "Moroni", age: 50},
        {name: "Tiancum", age: 43},
        {name: "Jacob", age: 27},
        {name: "Nephi", age: 29},
        {name: "Enos", age: 34}
    ];
    $scope.gridOptions = { 
        data: 'myData',
        columnDefs: [
            {field: 'name', displayName: 'Name'},
            {field:'age', displayName:'Age', cellTemplate: '<div ng-class="{green: row.getProperty(col.field) > 30}"><div class="ngCellText"><div ng-range value="row.getProperty(col.field)">{{ value }}</div></div></div>'}
        ]
    };
});

app.directive('ngRange', function(rangeValues) {
    return {
        restrict: 'EA',
        scope: {
            value: '='
        },
        link: function(scope, element, attrs) {
            // Adding values to the injected model.
            rangeValues.push({
                value: scope.value
            });

            // Adding values to the model on the parent scope
            scope.$parent.parentScopeRangeValues.push({
                value: scope.value
            })
        }
    }
});

Answer 6

In order to avoid calling the parent chain, you can simply utilize scope.$parent. Since scopes inherit from their parent scope in a prototypical manner, any non-value type can be safely accessed and modified. For a deeper understanding of how scope inheritance functions, refer to this informative response.

Below is the essential code for your reference. I have demonstrated the communication example through two methods; one involves dependency injection of a common model, while the other makes use of the parent scope.

View the working Plunker

var app = angular.module('myApp', ['ngGrid']);

app.factory('rangeValues', function() {
    return [];
});

app.controller('MyCtrl', function($scope, rangeValues) {
    $scope.factoryRangeValues = rangeValues;
    $scope.parentScopeRangeValues = [];
    $scope.myData = [
        {name: "Moroni", age: 50},
        {name: "Tiancum", age: 43},
        {name: "Jacob", age: 27},
        {name: "Nephi", age: 29},
        {name: "Enos", age: 34}
    ];
    $scope.gridOptions = { 
        data: 'myData',
        columnDefs: [
            {field: 'name', displayName: 'Name'},
            {field:'age', displayName:'Age', cellTemplate: '<div ng-class="{green: row.getProperty(col.field) > 30}"><div class="ngCellText"><div ng-range value="row.getProperty(col.field)">{{ value }}</div></div></div>'}
        ]
    };
});

app.directive('ngRange', function(rangeValues) {
    return {
        restrict: 'EA',
        scope: {
            value: '='
        },
        link: function(scope, element, attrs) {
            // Adding values to the injected model.
            rangeValues.push({
                value: scope.value
            });

            // Adding values to the model on the parent scope
            scope.$parent.parentScopeRangeValues.push({
                value: scope.value
            })
        }
    }
});

Communication within the intermediate scopes between the directive and the controller

Answer №1

Answer №2

Answer №3

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