Having trouble accessing $scope outside of the constructor in Typescript/AngularJS?

Why is it that I can't access $scope outside of the constructor, unless I use the fat arrow function? Is there a way to access $scope without using the fat arrow function?

namespace FooBar {
    export interface MyScope extends ng.IScope {
        message: string;
    }

    export class SandboxCtrl {
        static $inject = ["$scope", "$timeout"];
        private scope: MyScope;
        private timeout: ITimeoutService;
        constructor($scope: MyScope, $timeout: ng.ITimeoutService) {
            this.scope = $scope;
            this.timeout = $timeout;
            timeout(this.foo, 1000); // does not work
            timeout(this.bar, 1000); // works
        }

        public foo() {
            this.scope.message = "foo bar"; // does not work
        }

        bar = () => {
            this.scope.message = "foo bar"; // works
        }
    }
}

UPDATE Upon further investigation, I discovered that the issue was caused by the $timeout directive. I have updated my example accordingly.

Answer №1

Consider setting $scope as a variable within your controller component:

    export class PlaygroundController {
        static $inject = ["$scope"];
        constructor(private $scope: MyCustomScope) {

        }
    }

Answer №2

The issue was successfully resolved by utilizing the bind method to connect this to the function.

timeout(this.foo.bind(this), 1000);

Answer №3

When trying to use

timeout(this.foo, 1000); // does not work
, it may not work as intended.

The reason for this is that foo is an unbound function and the value of this will be determined by the caller.

To resolve this issue, it is recommended to use an arrow function instead 🌺

For Further Information

You can find more details on arrow functions by visiting https://basarat.gitbooks.io/typescript/content/docs/arrow-functions.html

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