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与同一对象中的另一个字段相关联，这可能吗？

Answer 1

1. 您可以在对象初始化后执行此操作：

   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);

2. 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

AFAIK 这是不可能的，但是您可以先创建 users 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,
}

干杯！！

Answer 3

您可以使用函数来执行此操作，如下所示：

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())