如何在对象内形成字段关联？

Question

const appData = {

    articleCount: 0,

    articles: [{      
      id: 1,
      title: 'How to make money',
      author: users[0].id,
      content: 'Gather income streams',
      createdat: '30/08/2018'      
    }],

    users: [{      
      id: 1,
      firstname: 'Michael',
      lastname: 'Lee',
      username: 'AuraDivitiae',
      articles: [{id: 1}]      
    }]

  }

我希望在我的appData对象和字段作者内部建立与同一对象内另一个字段的关联，这可能吗？

Answer 1

1. 您可以在对象初始化之后执行此操作：

   appData.articles [0] .author = appData.users [0] .id;

const appData = {

    articleCount: 0,

     users: [{

      id: 1,
      firstname: 'Michael',
      lastname: 'Lee',
      username: 'AuraDivitiae',
      articles: [{id: 1}]


    }],

    articles: [{

      id: 1,
      title: 'How to make money',
      author: null,
      content: 'Gather income streams',
      createdat: '30/08/2018'


    }]

   
  }
  
  appData.articles[0].author= appData.users[0].id;
  console.log(appData.articles[0].author);

1. 使用Getter

const appData = {

    articleCount: 0,

     users: [{

      id: 1,
      firstname: 'Michael',
      lastname: 'Lee',
      username: 'AuraDivitiae',
      articles: [{id: 1}]


    }],

    articles: [{

      id: 1,
      title: 'How to make money',
      content: 'Gather income streams',
      createdat: '30/08/2018',
      get author () {
         return appData.users[0].id;
      }


    }]

   
  }
  
  //appData.articles[0].author= appData.users[0].id;
  console.log(appData.articles[0].author);

Answer 2

这是不可能的，但是您可以先创建用户变量，然后在对象文字中引用它，如下所示：

const users = [{

  id: 1,
  firstname: 'Michael',
  lastname: 'Lee',
  username: 'AuraDivitiae',
  articles: [{id: 1}]


}]

const appData = {
  articleCount: 0,
  articles: [{
    id: 1,
    title: 'How to make money',
    author: users[0].id,
    content: 'Gather income streams',
    createdat: '30/08/2018'
  }],
  users,
}

欢呼！

Answer 3

您可以使用如下函数来实现它：

const appData = {
    
        articleCount: 0,
    
        articles: [{    
          id: 1,
          title: 'How to make money',
          author: ()=>appData.users[0].id,
          content: 'Gather income streams',
          createdat: '30/08/2018'    
        }],    
        users: [{    
          id: 1,
          firstname: 'Michael',
          lastname: 'Lee',
          username: 'AuraDivitiae',
          articles: [{id: 1}]    
        }]
    
      }
      
      console.log(appData.articles[0].author())