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<div class="min-h-screen p-16 bg-gray-100">
<!-- Check out a version without all the code -->
<!-- https://codepen.io/KevinBatdorf/pen/PoZOZPe -->
<!-- https://github.com/KevinBatdorf/alpine-observe-other-components -->
<h1 class="text-2xl font-bold mb-2">Find the total</h1>
<!-- This is it. No custom events -->
<div id="alpine-watcher" x-data="counterObserver()" x-init="start()" class="mb-6">
<p>Total: <span x-text="total"></span></p>
</div>
<p class="mb-6 max-w-lg">
Each box below is a separate Alpine component. There are no events being fired but you can observe the updates and react to them using a mutation observer.
<!-- One event just to reset the demo 🚀 -->
<button x-data="{}" @click="$dispatch('reset', {})" class="underline">Reset</button>
</p>
<!-- This is a generic component that just generates 9 child components -->
<div x-data="{ buttons: 9 }" class="grid md:grid-cols-2 lg:grid-cols-3 gap-10 max-w-lg">
<template x-for="buttons in Array.from({ length: buttons })">
<!-- These are all independant components -->
<button
x-data="counter()" @click="count++" @reset.window="count = 0" x-text="count"
class="bg-indigo-500 h-20 shadow-lg text-white font-extrabold text-4xl flex flex-col items-center justify-center uppercase">
</button>
</template>
</div>
</div>
[x-cloak] { display: none; }
function counter() {
return {
count: 0
}
}
function counterObserver() {
return {
total: 0,
alpines: [],
observer: null,
start() {
// Use an ID or another selector to focus on the components you want to ignore
// Parent components can't be ignored though, so you might want additional logic
// to ensure you have the correct components
this.alpines = document.querySelectorAll('[x-data]:not(#alpine-watcher)')
this.observer = new MutationObserver(mutations => {
// Everytime a mutation occurs we can run a function
this.updateTotalCount()
})
// Each Alpine needs to be observed separately
this.alpines && this.wrapAlpines()
},
wrapAlpines() {
this.alpines.forEach(alpine => {
this.observer.observe(alpine, {
attributes: true,
childList: true,
subtree: true,
})
})
},
updateTotalCount() {
// Refresh the Alpine components and grab the data
this.alpines = document.querySelectorAll('[x-data]:not(#alpine-watcher)')
this.total = Array.from(this.alpines).map(alpine => {
// This is an internal method where we can get the data.
// Just be warned that this functionality could change
// inside Alpine without notice
return alpine.__x.getUnobservedData().count
// We're filtering out 'undefined' values, specifically
// the components that don't have 'count'
}).filter(Boolean).reduce((a, b) => a + b, 0)
},
}
}
Also see: Tab Triggers