为...循环，并与阵列

Question

按照Mozilla docs内的对象解构，这里是如何使用解构一个for of循环中：

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，会是什么正确的解构语法被万一family物体位于一个阵列内，像这样：

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

（注额外组[方括号]的）

试图使用以解构：

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

给出在方括号的Unexpected token错误。

那么在这个例子中，我该如何使用解构来赋值给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，这是假设你只想要第一个成员。如果你想要更多，你可以使用其余的语法。

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); 
 
}

Answer 2

可以使用阵列解构（任何剩余的数组元素被简单地忽略）：

     // vv   vv 
for (var {name: n, family: [ {father: f} ] } of people) 
    // ... 

或者，由于阵列只是对象，可以使用对象与解构索引作为关键字：

     // vvvvv   vv 
for (var {name: n, family: { 0: {father: f} } } of people) 
    // ...