svelte/site/content/tutorial/08-stores/02-auto-subscriptions/text.md

---
title: Auto-subscriptions
---

The app in the previous example works, but there's a subtle bug — the store is subscribed to, but never unsubscribed. If the component was instantiated and destroyed many times, this would result in a *memory leak*.

Start by declaring `unsubscribe` in `App.svelte`:

```js
const unsubscribe = count.subscribe(value => {
	countValue = value;
});
```
> Calling a `subscribe` method returns an `unsubscribe` function.

You now declared `unsubscribe`, but it still needs to be called, for example through the `onDestroy` [lifecycle hook](/tutorial/ondestroy):

```html
<script>
	import { onDestroy } from 'svelte';
	import { count } from './stores.js';
	import Incrementer from './Incrementer.svelte';
	import Decrementer from './Decrementer.svelte';
	import Resetter from './Resetter.svelte';

	let countValue;

	const unsubscribe = count.subscribe(value => {
		countValue = value;
	});

	onDestroy(unsubscribe);
</script>

<h1>The count is {countValue}</h1>
```

It starts to get a bit boilerplatey though, especially if your component subscribes to multiple stores. Instead, Svelte has a trick up its sleeve — you can reference a store value by prefixing the store name with `$`:

```html
<script>
	import { count } from './stores.js';
	import Incrementer from './Incrementer.svelte';
	import Decrementer from './Decrementer.svelte';
	import Resetter from './Resetter.svelte';
</script>

<h1>The count is {$count}</h1>
```

> Auto-subscription only works with store variables that are declared (or imported) at the top-level scope of a component.

You're not limited to using `$count` inside the markup, either — you can use it anywhere in the `<script>` as well, such as in event handlers or reactive declarations.

> Any name beginning with `$` is assumed to refer to a store value. It's effectively a reserved character — Svelte will prevent you from declaring your own variables with a `$` prefix.