$emit - devhaeyeon/vueExample GitHub Wiki https://kr.vuejs.org/v2/guide/components.html#v-on%EC%9D%84-%EC%9D%B4%EC%9A%A9%ED%95%9C-%EC%82%AC%EC%9A%A9%EC%9E%90-%EC%A7%80%EC%A0%95-%EC%9D%B4%EB%B2%A4%ED%8A%B8 https://kr.vuejs.org/v2/api/index.html#vm-emit