computed-properties-set-value.html

<!DOCTYPE html>
<html lang="pt-BR">
  <head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Propriedades Armazenadas - Definindo um novo valor</title>
  </head>
  <body>
    
    <div id="computed">
      
      <h2>Nome: {{ person.firstName }}</h2>

      <h2>Nome completo (COMPUTED): {{ fullName }}</h2>

    </div>

    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

    <script>

      let app = new Vue({
        el: '#computed',
        data: {
          person: {
            firstName: 'Marcelo',
            lastName: 'Hoffmeister'
          }
        },
        computed: {
          fullName: {
            get: function() {
              return `${this.person.firstName} ${this.person.lastName}`
            },
            set: function(newValue) {
              let name = newValue.split(' ');

              this.person.firstName = name[0];
              this.person.lastName = name[1];
            }
          }
        }
      })

    </script>

  </body>
</html>