Why isn't my Angular directive able to access the parent controller's scope within its isolated scope?

I have meticulously followed the Angular documentation to implement a directive with an isolated scope that contains a few variables from the parent Controller's scope object.

app.controller('MainCtrl', function($scope) {
    $scope.name = 'Parent Name';

    $scope.pokie = {
        whyIs: "thisUndefined?"
    };
});

app.directive('parseObject', function() {

    var preLink = function($scope, el, att, controller) {
        console.log('[link] :: ', $scope);
    };

    var postLink = function($scope, el, att, controller) {
        console.log('[PostLink] :: ', $scope);
        console.log('[$Parent] :: ', $scope.$parent.name);
    };

    return {

        restrict: 'E',
        scope: {
            myPokie: '=pokie',
            name: '=name'
        },
        template: [
          '<div>',
          '<h1>Directive does not get parent scope</h1>',
          '<h1>{{ myPokie }}</h1>',
          '<h2>{{ name }}</h2>',
          '</div>'
        ].join(''),

        compile: function() {
            return {
                pre: preLink,
                post: postLink
            }
        }
    }
});

http://plnkr.co/edit/FpQtt9?p=preview

Could someone please help me identify what is causing issues in my code? Why are the values for 'myPokie' and 'name' returning as undefined in the directive's Isolate scope?

I have come across suggestions to use $scope.watch for this issue, but I am hesitant to do so since it should ideally work without such additional steps based on the official Angular directive documentation.

Answer №1

When you specify an isolated scope in your directive, it means you will pass values to the directive using attributes.

 scope: {
     myPokie: '=pokie',
     name: '=name'
 }

This indicates that your directive's scope will not inherit from the parent scope. The `pokie` attribute will provide the value for `myPokie`, while the `name` attribute will provide the value for `name` in your directive. The `=` symbol signifies two-way binding, meaning if the value of `myPokie` changes in the directive, it will also change in the parent controller. The same applies to the `name` attribute.

To use your directive in HTML, the element markup should be:

<parse-object pokie="pokie" name="name"></parse-object>

See working Plunkr example here

Answer №2

When utilizing isolated scope, it is crucial to ensure that the variables are being passed correctly. The issue lies within your HTML structure:

Please update your HTML code from:

<parse-object></parse-object>

To:

<parse-object pokie="pokie" name="name"></parse-object>

Remember, isolated scope retrieves its parameters from the DOM element. Hence, if you have defined inside the scope declaration:

myPokie: '=pokie',

This indicates that the myPokie variable should correspond to the pokie attribute within the scope. As for name: "=name", you can simplify it to name: "=" since they share the same identifier.

Plunker

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