A composable yaiku fungsi sing bisa dibalesi maneh kang ngenkapsulasi logika stately nggunakake Composition API. Miturut konvention jenenge useXxx lan mulih state reaktif plus fungsi — ngandakno sampeyan ngbagi logika antar komponen tanpa mixin utawa pengulangan.
{ ref, computed } ;
() {
count = (initial);
double = ( count. * );
() { count.++; }
() { count. = initial; }
{ count, double, increment, reset };
}
<script setup>
import { useCounter } from "@/composables/useCounter";
const { count, double, increment } = useCounter(10); // each call = independent state
</script>
<template>
<button @click="increment">{{ count }} (double: {{ double }})</button>
</template>
Saben komponen sing nutup useCounter() ndapatno pribadine count — composables nggawe state anyar per tawaran, beda saka variabel tingkat modul sing dibagi.
import { ref, onUnmounted } from "vue";
export function useMousePosition() {
const x = ref(0), y = ref(0);
const update = (e) => { x.value = e.pageX; y.value = e.pageY; };
window.addEventListener("mousemove", update); // set up
onUnmounted(() => window.removeEventListener("mousemove", update)); // auto cleanup!
return { x, y };
}
Composables bisa nggunakake lifecycle hooks, watchers, lan composables liya — lan krusyal, padha ngenkapsulasi beciking dhewe (onUnmounted), supaya konsumen ora kudu ngenuki.
Mixins (Vue 2): merged into the component — unclear where properties came from,
naming collisions between mixins, implicit dependencies
Composables: explicit imports + return values — clear sources, no collisions,
can be composed, fully typed in TypeScript
Composables yaiku jalan idiomatik kanggo ngekstrak lan baleni logika stateful ing Vue 3 — data fetching, form handling, mouse/scroll tracking, debouncing, lsp.
Pangatasi prakara reuse logika kanthi resik (eksplisit, tanpa tabrakan, composable, TypeScript-friendly) kana mixins Vue 2 gagal.
Merek alasan utama kenapa tim moro Composition API: logika sing dicocogake dadi fungsi sederhana kang bisa diuji tinimbang kode sing ecer utawa diduplikat.