如何对含嵌套对象数组的对象解构，获取指定元素属性？

你当前的问题出在获取enemyTitle的方式上——你把enemies数组当成普通对象来解构title属性，但实际上title是数组第4个元素（索引3）里的属性。

可以把所有需要的属性合并到一次解构操作中，无需重复拆分protagonist：

const {
  title,
  protagonist: {
    name: protagonistName,
    enemies: [ , , , { name: enemyName, title: enemyTitle } ]
  }
} = info;

解构逻辑说明： #

• enemies: [ , , , { ... } ] 里的三个逗号用于跳过数组前三个元素，直接定位到索引为3的目标元素，再解构它的name和title属性，分别赋值给enemyName和enemyTitle
• 顶层的title直接解构获取
• protagonist的name属性解构后重命名为protagonistName

修正后的完整函数： #

function nestedArrayAndObject() {
  const info = {
    title: 'Once Upon a Time',
    protagonist: {
      name: 'Emma Swan',
      enemies: [
        {name: 'Regina Mills', title: 'Evil Queen'},
        {name: 'Cora Mills', title: 'Queen of Hearts'},
        {name: 'Peter Pan', title: `The boy who wouldn't grow up`},
        {name: 'Zelena', title: 'The Wicked Witch'},
      ],
    },
  }
  
  const {
    title,
    protagonist: {
      name: protagonistName,
      enemies: [ , , , { name: enemyName, title: enemyTitle } ]
    }
  } = info;
 
  return `${enemyName} ${enemyTitle} is an enemy to ${protagonistName} in ${title}`;
}

nestedArrayAndObject(); // 返回 "Zelena The Wicked Witch is an enemy to Emma Swan in Once Upon a Time"

内容的提问来源于stack exchange，提问作者Adnan