Javascript数组在sort语句之前被排序

Question

编辑:这似乎与chrome控制台处理对象评估的方式有关，如
jsN00b

所述原来在这里

我按名字排序数组，然后按年龄，记录数组三次:在初始化之后，第二次和第三次是在分别按姓名和年龄排序数组之后。

第一个console.log()调用，然而，打印数组在其排序状态，但我期望的是数组在它的未排序状态。

不确定这是否与JavaScript在内存中处理数组的方式有关，还是它是一个bug?

代码:

function byField(field) {
return (objA, objB) => (objA[field] > objB[field] ? 1 : -1);
}
let users = [
{ name: "John", age: 20, surname: "Johnson" },
{ name: "Pete", age: 18, surname: "Peterson" },
{ name: "Ann", age: 19, surname: "Hathaway" },
];
console.log(users);
users.sort(byField("name"));
console.log(users);
users.sort(byField("age"));
console.log(users);

.as-console-wrapper { max-height: 100% !important; top: 0 }

预期输出:

//unsorted
[
{ name: "John", age: 20, surname: "Johnson" },
{ name: "Pete", age: 18, surname: "Peterson" },
{ name: "Ann", age: 19, surname: "Hathaway" },
];
//by name
[
{ name: "Ann", age: 19, surname: "Hathaway" },
{ name: "John", age: 20, surname: "Johnson" },
{ name: "Pete", age: 18, surname: "Peterson" },
];
//by age
[
{ name: "Pete", age: 18, surname: "Peterson" },
{ name: "Ann", age: 19, surname: "Hathaway" },
{ name: "John", age: 20, surname: "Johnson" },
];

实际输出:

//unsorted
[
{ name: "Pete", age: 18, surname: "Peterson" },
{ name: "Ann", age: 19, surname: "Hathaway" },
{ name: "John", age: 20, surname: "Johnson" },
];
//by name
[
{ name: "Pete", age: 18, surname: "Peterson" },
{ name: "Ann", age: 19, surname: "Hathaway" },
{ name: "John", age: 20, surname: "Johnson" },
];
//by age
[
{ name: "Pete", age: 18, surname: "Peterson" },
{ name: "Ann", age: 19, surname: "Hathaway" },
{ name: "John", age: 20, surname: "Johnson" },
];

Answer 1

方法Array.prototype.sort会改变初始数组。为了解决这个问题，您需要创建数组的副本，然后对该副本进行排序。就像下面的例子:

[...users].sort(byField("name"));