I'm looking for any manner of accessing the "parent" scope within a directive. Any combination of scope, transclude, require, passing in variables (or the scope itself) from above, etc. I'm totally willing to bend over backwards, but I want to avoid something totally hacky or unmaintainable. For example, I know I could do it right now by taking the $scope
from the preLink parameters and iterating over it's $sibling
scopes to find the conceptual "parent".
What I really want is to be able to $watch
an expression in the parent scope. If I can do that, then I can accomplish what I'm trying to do over here: AngularJS - How to render a partial with variables?
An important note is that the directive must be re-usable within the same parent scope. Therefore the default behavior (scope: false) doesn't work for me. I need an individual scope per instance of the directive, and then I need to $watch
a variable that lives in the parent scope.
A code sample is worth 1000 words, so:
app.directive('watchingMyParentScope', function() { return { require: /* ? */, scope: /* ? */, transclude: /* ? */, controller: /* ? */, compile: function(el,attr,trans) { // Can I get the $parent from the transclusion function somehow? return { pre: function($s, $e, $a, parentControl) { // Can I get the $parent from the parent controller? // By setting this.$scope = $scope from within that controller? // Can I get the $parent from the current $scope? // Can I pass the $parent scope in as an attribute and define // it as part of this directive's scope definition? // What don't I understand about how directives work and // how their scope is related to their parent? }, post: function($s, $e, $a, parentControl) { // Has my situation improved by the time the postLink is called? } } } }; });
The directive scope uses prefixes to achieve that. Using prefixes helps establish a two-way or one-way binding between parent and directive scopes, and also make calls to parent scope methods. To access any data in the parent scope requires passing the data at two places – the directive scope and the directive tag.
In a nutshell: You cannot access child scopes from a parent scope. Your solutions: Define properties in parents and access them from children (read the link above) Use a service to share state.
Angular scopes include a variable called $parent (i.e. $scope. $parent ) that refer to the parent scope of a controller. If a controller is at the root of the application, the parent would be the root scope ( $rootScope ). Child controllers can therefore modify the parent scope since they access to it.
Isolate Scope: If the need is to reuse the component (directive) throughout your app, consider creating isolate scopes using scope option. The concept of isolate scope is used to separate the scope inside a directive from the scope outside.
See What are the nuances of scope prototypal / prototypical inheritance in AngularJS?
To summarize: the way a directive accesses its parent ($parent
) scope depends on the type of scope the directive creates:
default (scope: false
) - the directive does not create a new scope, so there is no inheritance here. The directive's scope is the same scope as the parent/container. In the link function, use the first parameter (typically scope
).
scope: true
- the directive creates a new child scope that prototypically inherits from the parent scope. Properties that are defined on the parent scope are available to the directive scope
(because of prototypal inheritance). Just beware of writing to a primitive scope property -- that will create a new property on the directive scope (that hides/shadows the parent scope property of the same name).
scope: { ... }
- the directive creates a new isolate/isolated scope. It does not prototypically inherit the parent scope. You can still access the parent scope using $parent
, but this is not normally recommended. Instead, you should specify which parent scope properties (and/or function) the directive needs via additional attributes on the same element where the directive is used, using the =
, @
, and &
notation.
transclude: true
- the directive creates a new "transcluded" child scope, which prototypically inherits from the parent scope. If the directive also creates an isolate scope, the transcluded and the isolate scopes are siblings. The $parent
property of each scope references the same parent scope.
Angular v1.3 update: If the directive also creates an isolate scope, the transcluded scope is now a child of the isolate scope. The transcluded and isolate scopes are no longer siblings. The $parent
property of the transcluded scope now references the isolate scope.
The above link has examples and pictures of all 4 types.
You cannot access the scope in the directive's compile function (as mentioned here: https://github.com/angular/angular.js/wiki/Dev-Guide:-Understanding-Directives). You can access the directive's scope in the link function.
Watching:
For 1. and 2. above: normally you specify which parent property the directive needs via an attribute, then $watch it:
<div my-dir attr1="prop1"></div>
scope.$watch(attrs.attr1, function() { ... });
If you are watching an object property, you'll need to use $parse:
<div my-dir attr2="obj.prop2"></div>
var model = $parse(attrs.attr2); scope.$watch(model, function() { ... });
For 3. above (isolate scope), watch the name you give the directive property using the @
or =
notation:
<div my-dir attr3="{{prop3}}" attr4="obj.prop4"></div>
scope: { localName3: '@attr3', attr4: '=' // here, using the same name as the attribute }, link: function(scope, element, attrs) { scope.$watch('localName3', function() { ... }); scope.$watch('attr4', function() { ... });
Accessing controller method means accessing a method on parent scope from directive controller/link/scope.
If the directive is sharing/inheriting the parent scope then it is quite straight forward to just invoke a parent scope method.
Little more work is required when you want to access parent scope method from Isolated directive scope.
There are few options (may be more than listed below) to invoke a parent scope method from isolated directives scope or watch parent scope variables (option#6 specially).
Note that I used link function
in these examples but you can use a directive controller
as well based on requirement.
Option#1. Through Object literal and from directive html template
index.html
<!DOCTYPE html> <html ng-app="plunker"> <head> <meta charset="utf-8" /> <title>AngularJS Plunker</title> <script>document.write('<base href="' + document.location + '" />');</script> <link rel="stylesheet" href="style.css" /> <script data-require="[email protected]" src="https://code.angularjs.org/1.3.9/angular.js" data-semver="1.3.9"></script> <script src="app.js"></script> </head> <body ng-controller="MainCtrl"> <p>Hello {{name}}!</p> <p> Directive Content</p> <sd-items-filter selected-items="selectedItems" selected-items-changed="selectedItemsChanged(selectedItems)" items="items"> </sd-items-filter> <P style="color:red">Selected Items (in parent controller) set to: {{selectedItemsReturnedFromDirective}} </p> </body> </html>
itemfilterTemplate.html
<select ng-model="selectedItems" multiple="multiple" style="height: 200px; width: 250px;" ng-change="selectedItemsChanged({selectedItems:selectedItems})" ng-options="item.id as item.name group by item.model for item in items | orderBy:'name'"> <option>--</option> </select>
app.js
var app = angular.module('plunker', []); app.directive('sdItemsFilter', function() { return { restrict: 'E', scope: { items: '=', selectedItems: '=', selectedItemsChanged: '&' }, templateUrl: "itemfilterTemplate.html" } }) app.controller('MainCtrl', function($scope) { $scope.name = 'TARS'; $scope.selectedItems = ["allItems"]; $scope.selectedItemsChanged = function(selectedItems1) { $scope.selectedItemsReturnedFromDirective = selectedItems1; } $scope.items = [{ "id": "allItems", "name": "All Items", "order": 0 }, { "id": "CaseItem", "name": "Case Item", "model": "PredefinedModel" }, { "id": "Application", "name": "Application", "model": "Bank" }] });
working plnkr: http://plnkr.co/edit/rgKUsYGDo9O3tewL6xgr?p=preview
Option#2. Through Object literal and from directive link/scope
index.html
<!DOCTYPE html> <html ng-app="plunker"> <head> <meta charset="utf-8" /> <title>AngularJS Plunker</title> <script>document.write('<base href="' + document.location + '" />');</script> <link rel="stylesheet" href="style.css" /> <script data-require="[email protected]" src="https://code.angularjs.org/1.3.9/angular.js" data-semver="1.3.9"></script> <script src="app.js"></script> </head> <body ng-controller="MainCtrl"> <p>Hello {{name}}!</p> <p> Directive Content</p> <sd-items-filter selected-items="selectedItems" selected-items-changed="selectedItemsChanged(selectedItems)" items="items"> </sd-items-filter> <P style="color:red">Selected Items (in parent controller) set to: {{selectedItemsReturnedFromDirective}} </p> </body> </html>
itemfilterTemplate.html
<select ng-model="selectedItems" multiple="multiple" style="height: 200px; width: 250px;" ng-change="selectedItemsChangedDir()" ng-options="item.id as item.name group by item.model for item in items | orderBy:'name'"> <option>--</option> </select>
app.js
var app = angular.module('plunker', []); app.directive('sdItemsFilter', function() { return { restrict: 'E', scope: { items: '=', selectedItems: '=', selectedItemsChanged: '&' }, templateUrl: "itemfilterTemplate.html", link: function (scope, element, attrs){ scope.selectedItemsChangedDir = function(){ scope.selectedItemsChanged({selectedItems:scope.selectedItems}); } } } }) app.controller('MainCtrl', function($scope) { $scope.name = 'TARS'; $scope.selectedItems = ["allItems"]; $scope.selectedItemsChanged = function(selectedItems1) { $scope.selectedItemsReturnedFromDirective = selectedItems1; } $scope.items = [{ "id": "allItems", "name": "All Items", "order": 0 }, { "id": "CaseItem", "name": "Case Item", "model": "PredefinedModel" }, { "id": "Application", "name": "Application", "model": "Bank" }] });
working plnkr: http://plnkr.co/edit/BRvYm2SpSpBK9uxNIcTa?p=preview
Option#3. Through Function reference and from directive html template
index.html
<!DOCTYPE html> <html ng-app="plunker"> <head> <meta charset="utf-8" /> <title>AngularJS Plunker</title> <script>document.write('<base href="' + document.location + '" />');</script> <link rel="stylesheet" href="style.css" /> <script data-require="[email protected]" src="https://code.angularjs.org/1.3.9/angular.js" data-semver="1.3.9"></script> <script src="app.js"></script> </head> <body ng-controller="MainCtrl"> <p>Hello {{name}}!</p> <p> Directive Content</p> <sd-items-filter selected-items="selectedItems" selected-items-changed="selectedItemsChanged" items="items"> </sd-items-filter> <P style="color:red">Selected Items (in parent controller) set to: {{selectedItemsReturnFromDirective}} </p> </body> </html>
itemfilterTemplate.html
<select ng-model="selectedItems" multiple="multiple" style="height: 200px; width: 250px;" ng-change="selectedItemsChanged()(selectedItems)" ng-options="item.id as item.name group by item.model for item in items | orderBy:'name'"> <option>--</option> </select>
app.js
var app = angular.module('plunker', []); app.directive('sdItemsFilter', function() { return { restrict: 'E', scope: { items: '=', selectedItems:'=', selectedItemsChanged: '&' }, templateUrl: "itemfilterTemplate.html" } }) app.controller('MainCtrl', function($scope) { $scope.name = 'TARS'; $scope.selectedItems = ["allItems"]; $scope.selectedItemsChanged = function(selectedItems1) { $scope.selectedItemsReturnFromDirective = selectedItems1; } $scope.items = [{ "id": "allItems", "name": "All Items", "order": 0 }, { "id": "CaseItem", "name": "Case Item", "model": "PredefinedModel" }, { "id": "Application", "name": "Application", "model": "Bank" }] });
working plnkr: http://plnkr.co/edit/Jo6FcYfVXCCg3vH42BIz?p=preview
Option#4. Through Function reference and from directive link/scope
index.html
<!DOCTYPE html> <html ng-app="plunker"> <head> <meta charset="utf-8" /> <title>AngularJS Plunker</title> <script>document.write('<base href="' + document.location + '" />');</script> <link rel="stylesheet" href="style.css" /> <script data-require="[email protected]" src="https://code.angularjs.org/1.3.9/angular.js" data-semver="1.3.9"></script> <script src="app.js"></script> </head> <body ng-controller="MainCtrl"> <p>Hello {{name}}!</p> <p> Directive Content</p> <sd-items-filter selected-items="selectedItems" selected-items-changed="selectedItemsChanged" items="items"> </sd-items-filter> <P style="color:red">Selected Items (in parent controller) set to: {{selectedItemsReturnedFromDirective}} </p> </body> </html>
itemfilterTemplate.html
<select ng-model="selectedItems" multiple="multiple" style="height: 200px; width: 250px;" ng-change="selectedItemsChangedDir()" ng-options="item.id as item.name group by item.model for item in items | orderBy:'name'"> <option>--</option> </select>
app.js
var app = angular.module('plunker', []); app.directive('sdItemsFilter', function() { return { restrict: 'E', scope: { items: '=', selectedItems: '=', selectedItemsChanged: '&' }, templateUrl: "itemfilterTemplate.html", link: function (scope, element, attrs){ scope.selectedItemsChangedDir = function(){ scope.selectedItemsChanged()(scope.selectedItems); } } } }) app.controller('MainCtrl', function($scope) { $scope.name = 'TARS'; $scope.selectedItems = ["allItems"]; $scope.selectedItemsChanged = function(selectedItems1) { $scope.selectedItemsReturnedFromDirective = selectedItems1; } $scope.items = [{ "id": "allItems", "name": "All Items", "order": 0 }, { "id": "CaseItem", "name": "Case Item", "model": "PredefinedModel" }, { "id": "Application", "name": "Application", "model": "Bank" }] });
working plnkr: http://plnkr.co/edit/BSqx2J1yCY86IJwAnQF1?p=preview
Option#5: Through ng-model and two way binding, you can update parent scope variables.. So, you may not require to invoke parent scope functions in some cases.
index.html
<!DOCTYPE html> <html ng-app="plunker"> <head> <meta charset="utf-8" /> <title>AngularJS Plunker</title> <script>document.write('<base href="' + document.location + '" />');</script> <link rel="stylesheet" href="style.css" /> <script data-require="[email protected]" src="https://code.angularjs.org/1.3.9/angular.js" data-semver="1.3.9"></script> <script src="app.js"></script> </head> <body ng-controller="MainCtrl"> <p>Hello {{name}}!</p> <p> Directive Content</p> <sd-items-filter ng-model="selectedItems" selected-items-changed="selectedItemsChanged" items="items"> </sd-items-filter> <P style="color:red">Selected Items (in parent controller) set to: {{selectedItems}} </p> </body> </html>
itemfilterTemplate.html
<select ng-model="selectedItems" multiple="multiple" style="height: 200px; width: 250px;" ng-options="item.id as item.name group by item.model for item in items | orderBy:'name'"> <option>--</option> </select>
app.js
var app = angular.module('plunker', []); app.directive('sdItemsFilter', function() { return { restrict: 'E', scope: { items: '=', selectedItems: '=ngModel' }, templateUrl: "itemfilterTemplate.html" } }) app.controller('MainCtrl', function($scope) { $scope.name = 'TARS'; $scope.selectedItems = ["allItems"]; $scope.items = [{ "id": "allItems", "name": "All Items", "order": 0 }, { "id": "CaseItem", "name": "Case Item", "model": "PredefinedModel" }, { "id": "Application", "name": "Application", "model": "Bank" }] });
working plnkr: http://plnkr.co/edit/hNui3xgzdTnfcdzljihY?p=preview
Option#6: Through $watch
and $watchCollection
It is two way binding for items
in all above examples, if items are modified in parent scope, items in directive would also reflect the changes.
If you want to watch other attributes or objects from parent scope, you can do that using $watch
and $watchCollection
as given below
html
<!DOCTYPE html> <html ng-app="plunker"> <head> <meta charset="utf-8" /> <title>AngularJS Plunker</title> <script> document.write('<base href="' + document.location + '" />'); </script> <link rel="stylesheet" href="style.css" /> <script data-require="[email protected]" src="https://code.angularjs.org/1.3.9/angular.js" data-semver="1.3.9"></script> <script src="app.js"></script> </head> <body ng-controller="MainCtrl"> <p>Hello {{user}}!</p> <p>directive is watching name and current item</p> <table> <tr> <td>Id:</td> <td> <input type="text" ng-model="id" /> </td> </tr> <tr> <td>Name:</td> <td> <input type="text" ng-model="name" /> </td> </tr> <tr> <td>Model:</td> <td> <input type="text" ng-model="model" /> </td> </tr> </table> <button style="margin-left:50px" type="buttun" ng-click="addItem()">Add Item</button> <p>Directive Contents</p> <sd-items-filter ng-model="selectedItems" current-item="currentItem" name="{{name}}" selected-items-changed="selectedItemsChanged" items="items"></sd-items-filter> <P style="color:red">Selected Items (in parent controller) set to: {{selectedItems}}</p> </body> </html>
script app.js
var app = angular.module('plunker', []);
app.directive('sdItemsFilter', function() { return { restrict: 'E', scope: { name: '@', currentItem: '=', items: '=', selectedItems: '=ngModel' }, template: '<select ng-model="selectedItems" multiple="multiple" style="height: 140px; width: 250px;"' + 'ng-options="item.id as item.name group by item.model for item in items | orderBy:\'name\'">' + '<option>--</option> </select>', link: function(scope, element, attrs) { scope.$watchCollection('currentItem', function() { console.log(JSON.stringify(scope.currentItem)); }); scope.$watch('name', function() { console.log(JSON.stringify(scope.name)); }); } } }) app.controller('MainCtrl', function($scope) { $scope.user = 'World'; $scope.addItem = function() { $scope.items.push({ id: $scope.id, name: $scope.name, model: $scope.model }); $scope.currentItem = {}; $scope.currentItem.id = $scope.id; $scope.currentItem.name = $scope.name; $scope.currentItem.model = $scope.model; } $scope.selectedItems = ["allItems"]; $scope.items = [{ "id": "allItems", "name": "All Items", "order": 0 }, { "id": "CaseItem", "name": "Case Item", "model": "PredefinedModel" }, { "id": "Application", "name": "Application", "model": "Bank" }] });
You can always refer AngularJs documentation for detailed explanations about directives.
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