$store

You can use $store to conveniently access global Alpine stores registered using Alpine.store(...). For example:

<button x-data @click="$store.darkMode.toggle()">Toggle Dark Mode</button>

...

<div x-data :class="$store.darkMode.on && 'bg-black'">
    ...
</div>


<script>
    document.addEventListener('alpine:init', () => {
        Alpine.store('darkMode', {
            on: false,

            toggle() {
                this.on = ! this.on
            }
        })
    })
</script>

Given that we've registered the darkMode store and set on to "false", when the <button> is pressed, on will be "true" and the background color of the page will change to black.

Single-value stores

If you don't need an entire object for a store, you can set and use any kind of data as a store.

Here's the example from above but using it more simply as a boolean value:

<button x-data @click="$store.darkMode = ! $store.darkMode">Toggle Dark Mode</button>

...

<div x-data :class="$store.darkMode && 'bg-black'">
    ...
</div>


<script>
    document.addEventListener('alpine:init', () => {
        Alpine.store('darkMode', false)
    })
</script>

→ Read more about Alpine stores