意外令牌：使用地图形成对象数组[重复]

Posted 2023-02-22

【中文标题】意外令牌：使用地图形成对象数组[重复]

【英文标题】：unexpected token : using map to form array of object [duplicate]

【发布时间】：2017-11-06 03:21:04

【问题描述】：

我想制作这个

[
        name: "james", age: 10,
        name: "john", age: 12,
        name: "johnny", age: 56
    ]

我下面的代码失败了，得到了预期的令牌？

let x = [
    name: "james", age: 10, school: "London",
    name: "john", age: 12, school: "India",
    name: "johnny", age: 56, school: "USA"
]

let y = x.map(obj => name:obj.name, age:obj.age)

console.log(y)

【参考方案1】：

你错过了 () 这样的更改 (name:obj.name, age:obj.age)

您必须将返回的对象文字包装到括号中。否则 花括号将被视为表示函数的主体。下一个 作品：

Reference question

let x = [
    name: "james", age: 10, school: "London",
    name: "john", age: 12, school: "India",
    name: "johnny", age: 56, school: "USA"
]

let y = x.map(obj => (name:obj.name, age:obj.age))

console.log(y)

【讨论】：

new Object(name:obj.name, age:obj.age) 也可以吗？

@AyoubLaazazi .. 当然可以。但是() 就足够了。短格式声明。

【参考方案2】：

使用箭头表达式创建对象时，您需要将主体包裹在括号中，否则将被解析为箭头函数：

let y = x.map(obj => (name: obj.name, age: obj.age));

【参考方案3】：

作为参考，这也可以，并且是一样的：

let x = [
    name: "james", age: 10, school: "London",
    name: "john", age: 12, school: "India",
    name: "johnny", age: 56, school: "USA"
];

let y = x.map(obj => 
  return  name:obj.name, age:obj.age ;
);

console.log(y);