Save states to localStorage (for Vue 2)

my-file.vue

// change `nameState`
export default {
  data: () => ({
    nameState: 0,
  }),
  watch: {
    nameState(state) {
      localStorage.setItem('nameState', JSON.stringify(state));
    },
  },
  mounted() {
    if (localStorage.nameState) {
      this.nameState = JSON.parse(localStorage.getItem('nameState'));
    }
  },
}