for ...使用数组内的对象进行迭代和解构

Question

根据Mozilla文档,这里是如何在for of循环中使用解构:

var people = [
  {
    name: 'Mike Smith',
    family: {
      mother: 'Jane Smith',
      father: 'Harry Smith',
      sister: 'Samantha Smith'
    },
    age: 35
  },
  {
    name: 'Tom Jones',
    family: {
      mother: 'Norah Jones',
      father: 'Richard Jones',
      brother: 'Howard Jones'
    },
    age: 25
  }
];

for (var {name: n, family: {father: f}} of people) {
  console.log('Name: ' + n + ', Father: ' + f);
}

// "Name: Mike Smith, Father: Harry Smith"
// "Name: Tom Jones, Father: Richard Jones"

我的问题是,如果family对象位于数组中,正确的解构语法是什么,如下所示:

var people = [
  {
    name: 'Tom Jones',
    family: [
     {
      mother: 'Norah Jones',
      father: 'Richard Jones',
      brother: 'Howard Jones'
     }
    ],
    age: 25
  }
];

(注意额外的[方括号])

尝试使用以下方法进行结构化:

for (var {name: n, family[0]: {father: f}} of people) {
  console.log('Name: ' + n + ', Father: ' + f);
}

Unexpected token在方括号处给出错误.

所以在这个例子中,我如何使用解构来赋值f？

Answer 1

您希望表示数组结构,而不是数组索引访问.

var people = [{
  name: 'Tom Jones',
  family: [{
    mother: 'Norah Jones',
    father: 'Richard Jones',
    brother: 'Howard Jones'
  }],
  age: 25
}];

// Describe the structure -v-----------v
for (var {name: n, family: [{father: f}]} of people) {
  console.log('Name: ' + n + ', Father: ' + f);
}

当然,这假设您只想要第一个成员.如果您需要更多,可以使用其余语法.

var people = [{
  name: 'Tom Jones',
  family: [{
    mother: 'Norah Jones',
    father: 'Richard Jones',
    brother: 'Howard Jones'
  }],
  age: 25
}];

for (var {name: n, family: [{father: f}, ...rem]} of people) {
  console.log('Name: ' + n + ', Father: ' + f);
  console.log("Remaining values: %s", rem.length);
}