What is the best way to expose services beyond the constructor in Angular?

I'm facing an issue with my code. In Ionic with Angular, I usually access Angular services in the constructor after injecting them like this:

export class HomeController {
    static $inject = [
        '$scope',
        '$state'
    ];

    constructor(
       public $scope : any,
       public $state : any
    ) {
        this.$state.go('test');
        this.$scope.changeController = this.changeController;
    }

    changeController() {
        console.log("change controller");
    };
}

However, when I modify it to the following structure, it stops working:

export class HomeController {
    static $inject = [
        '$scope',
        '$state'
    ];

    constructor(
       public $scope : any,
       public $state : any
    ) {
        this.$scope.changeController = this.changeController;
    }

    changeController() {
        console.log("change controller");
        this.$state.go('test'); // This line fails
    };
}

An error is thrown:

Error: undefined is not an object (evaluating 'this.$state.go')

Any suggestions on how to resolve this?

Additionally, is it appropriate to add the changeController function to the scope, or is there a simpler way to make it accessible to a template?

Thank you in advance

Answer №1

If you are facing the problem of incorrect value for this, it is often caused by a misunderstanding of ES6 classes. Consider using lambda to ensure lexical scoping:

  updateHandler = () => {
    console.log("update handler");
    this.$state.transitionTo('test'); // Error occurs here
  };

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