How to operate functions of component controllers from outside

I have a component with a function inside:

app.component("myComponent", {
    templateUrl: "myComponent.html",
    controller: function() {
        this.addApp = function (arg) {
            console.log(arg);
        };
    }
})

I would like to operate that function from outside the component:

<my-component>
</my-component>

<button type="button" ng-click="something.addApp('Cheese')"
        class="btn-sm btn-default no-modal" >
  Add Application
</button>

How to do that?

Source: AngularJS