callback-example.js

delete_booking(code) {
      this.get_id_by_code(code, (id) => {
        this.$store.dispatch('delete_booking', id)
          .then(() => {
            this.$toasted.show('Deleted successfully');
            this.status = false;
          })
          .catch(() => this.$toasted.show('Something went wrong'));
      });
    },
    get_id_by_code(code, callback) {
      const database = firebase.database();
      database.ref('booking')
        .orderByChild('booking_code')
        .equalTo(code)
        .on('value', (snapshot) => {
          const ids = Object.keys(snapshot.val());
          callback(ids[0]);
        });
    },