import { ref, onMounted } from 'vue';

export function useCounter() {
    const count = ref(0);
    const increment = () => count.value++;
    onMounted(() => console.log('hook mounted'));
    return { count, increment };
}

watch(() => state.value, (newVal, oldVal) => { ... })

watchEffect(() => {
    console.log(state.value + ' changed');
});

provide('key', value)

const val = inject('key')