# Listen on state changes

To listen on state changes, you need to attach a "hook" in the store using the `hook` method. The hook will trigger depending on what action query you passed in it.

To see that in action, here is the simple example of a hook that queries the actions `INCREMENT_COUNT` and `DECREMENT_COUNT`.

{% code title="your-controller.js" %}

```javascript
import { CounterStore } from 'counter-store';

function YourController($scope, counterStore) {
  counterStore.hook('INCREMENT_COUNT', (state) => {
    $scope.count = state.count;
  });

  counterStore.hook('DECREMENT_COUNT', ({ count }) => {
    $scope.count = count;
  });
}

angular
  .module('App', [])
  .controller('YourController', YourController);
```

{% endcode %}

{% hint style="warning" %}
All the attached hook has an initial phase which makes its callback to run automatically after successfully registered.
{% endhint %}

{% hint style="info" %}
To check if the hook callback is currently running on its initial phase, you can use the second argument from the callback function which determines if it is an initial phase.
{% endhint %}

As you can notice in the first example, you update the same scope variable (which is the `count`) using two different hooks that listen on `INCREMENT_COUNT` and `DECREMENT_COUNT`, you can simplify that by using a wild card, array, or regular expression action query.

{% code title="your-controller.js" %}

```javascript
import { CounterStore } from 'counter-store';

function YourController($scope, counterStore) {
  // Using an array of action
  counterStore.hook(['INCREMENT_COUNT', 'DECREMENT_COUNT'], (state) => {
    $scope.count = state.count;
  });
  
  // Using a wild card
  counterStore.hook('*', (state) => {
    $scope.count = state.count;
  });
  
  // Using a regular expression
  counterStore.hook(/^(IN|DE)CREMENT_COUNT$/, (state) => {
    $scope.count = state.count;
  });
}

angular
  .module('App', [])
  .controller('YourController', YourController);
```

{% endcode %}

{% hint style="warning" %}
Be careful of using wild card (\*) action query. It makes the hook callback to always responds to all dispatched actions, even the one you are not expecting.
{% endhint %}


---

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