數(shù)組的默認排序在處理數(shù)字時可能產(chǎn)生意外結(jié)果，因為sort()方法會將元素轉(zhuǎn)換為字符串并按Unicode值排序；要正確排序數(shù)字，必須使用比較函數(shù)；對于數(shù)字升序排列，使用(a, b) => a - b；對于降序排列，使用(a, b) => b - a；字符串排序默認有效，但若需忽略大小寫，應(yīng)使用localeCompare()方法；排序?qū)ο髷?shù)組時，可通過訪問屬性值并結(jié)合比較函數(shù)實現(xiàn)，如按年齡排序使用(a, b) => a.age - b.age；為避免修改原數(shù)組，應(yīng)先使用擴展運算符創(chuàng)建副本再排序；復(fù)雜排序（如多字段排序）可通過邏輯或運算符鏈式處理，如a.age - b.age || a.name.localeCompare(b.name)；總之，使用比較函數(shù)能實現(xiàn)對排序行為的完全控制，尤其在處理數(shù)字或自定義邏輯時必不可少。

Sorting an array in JavaScript is straightforward using the built-in sort() method, but there are some important details to understand—especially how it works by default and how to customize it.

How the sort() method works

By default, the sort() method converts array elements to strings and sorts them in ascending order based on Unicode values. This works fine for strings, but can give unexpected results with numbers.

const numbers = [10, 5, 30, 20];
numbers.sort();
console.log(numbers); // [10, 20, 30, 5] ← Not correct numerically!

Why? Because '10', '20', '30', and '5' are compared as strings, and '5' comes after '3' in Unicode order.

Sorting numbers correctly with a compare function

To sort numbers properly, you need to provide a compare function:

const numbers = [10, 5, 30, 20];
numbers.sort((a, b) => a - b);
console.log(numbers); // [5, 10, 20, 30] ?

• If the result is negative, a comes first.
• If positive, b comes first.
• If zero, no change.

For descending order:

numbers.sort((a, b) => b - a); // [30, 20, 10, 5]

Sorting strings

For strings, sort() works well by default:

const fruits = ['banana', 'apple', 'cherry'];
fruits.sort();
console.log(fruits); // ['apple', 'banana', 'cherry']

For case-insensitive sorting, use localeCompare():

const words = ['Banana', 'apple', 'Cherry'];
words.sort((a, b) => a.localeCompare(b));
console.log(words); // ['apple', 'Banana', 'Cherry']

Sorting objects by a property

You can sort arrays of objects by a specific property:

const users = [
  { name: 'John', age: 30 },
  { name: 'Anna', age: 25 },
  { name: 'Tom', age: 35 }
];

users.sort((a, b) => a.age - b.age);
// Sorts by age ascending

Important notes

• sort() modifies the original array. To avoid that, create a copy first:

  const sorted = [...numbers].sort((a, b) => a - b);

• For more complex sorting (like multiple fields), chain conditions:

  users.sort((a, b) => a.age - b.age || a.name.localeCompare(b.name));

  Basically, use sort() with a compare function for full control—especially with numbers or custom logic. Default string-based sorting is fine for simple string arrays but can trip you up otherwise.

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