The template stays a template, the data stays reactive

A Vue component is three blocks in one `.vue`. Markup stays markup.

Reactivity isn't "magic". Change `.value` on a ref and the template redraws itself.

v-for without :key is a trap. Computed is a cached formula, not a method called "at every sneeze".

@click calls a function. .prevent on a form, otherwise a reload.

You type — the ref changes. A checkbox is a boolean, not a string.

Computed is a formula. watch is for calling an API when the id changed.

defineProps reads. defineEmits notifies the parent. Don't write into a prop.

After it appears in the DOM — onMounted. Fetch there, or in a watch on the id.