js中如何对数组进行排序-小浪学习网

<p></p> <p>在JavaScript中对数组进行精确排序的核心方法是使用Array.prototype.sort()并传入自定义比较函数。1. 对于数字排序，必须提供比较函数(a, b) => a – b实现升序，或(b – a)实现降序，否则默认按字符串unicode码点排序会导致9排在10之后等错误结果。2. 对复杂对象排序时，比较函数应根据对象属性（如age或name）进行逻辑判断，支持多级排序：先按主要字段比较，相等时再按次要字段，例如先按age升序再按name字母顺序<a >排列</a>。3. 字符串排序推荐使用localecompare方法以正确处理国际化字符，如a.localecompare(b, ‘zh-cn’)可支持中文拼音排序。4. sort()会修改原数组，若需保留原数组应使用[…arr].sort()或slice().sort()创建副本，或使用es2023新增的tosorted()方法直接返回新数组。5. 排序稳定性不被所有环境保证，相等元素的相对位置可能变化，依赖此行为时需额外处理。6. 高级排序需求可通过映射自定义顺序（如状态映射为数字）或多字段组合实现，也可借助lodash等库的sortby方法简化操作。7. 性能方面，sort()平均时间复杂度为o(n log n)，但应避免在比较函数中执行耗时操作，且对超大数组建议在后端处理以优化性能。</p> <p><img src=”https://img.php.cn/upload/article/001/221/864/175427352227818.png” alt=”JS中如何对数组进行排序”></p> <p>在JavaScript中，对数组进行排序最常用的方法是使用其内置的 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>Array.prototype.sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 方法。这个方法会直接修改原数组，并返回一个指向原数组的引用。它的默认行为是将数组元素转换为字符串，然后按照UTF-16码点值进行升序排列，这对于数字排序来说常常不是我们想要的结果，所以多数时候我们需要提供一个自定义的比较函数。</p> <img src=”https://img.php.cn/upload/article/001/221/864/175427352250278.png” alt=”js中如何对数组进行排序”><h3>解决方案</h3> <p>JavaScript的 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>Array.prototype.sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 方法是处理数组排序的核心。当你直接调用 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>arr.sort()</pre><div class=”contentsignin”></div></div> 而不传入任何参数时，它会把数组里的所有元素都当成字符串来处理，然后按照它们的Unicode码点进行排序。这听起来有点儿抽象，但说白了，就是它会把数字 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>9</pre><div class=”contentsignin”></div></div> 看作字符串 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>’9′</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div>，把 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>10</pre><div class=”contentsignin”></div></div> 看作字符串 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>’10′</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div>，那么在字符串比较中，<div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>’10′</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 会排在 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>’9′</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 前面，因为 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>’1′</pre><div class=”contentsignin”></div></div> 比 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>’9′</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 小。这显然不是我们对数字排序的预期。</p> <p>因此，为了实现真正的数字排序，或者更复杂的对象排序，我们必须给 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 方法传入一个比较函数（<div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>compareFunction</pre><div class=”contentsignin”></div></div>）。这个函数接收两个参数 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>a</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 和 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>b</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div>，它们代表了数组中将要进行比较的两个元素。</p> <img src=”https://img.php.cn/upload/article/001/221/864/175427352347707.png” alt=”js中如何对数组进行排序”><p>比较函数的返回值决定了 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>a</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 和 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>b</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 的相对顺序：</p> <ul> <li>如果 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>compareFunction(a, b)</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 返回一个<strong>负数</strong>，那么 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>a</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 会排在 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>b</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 的前面。</li> <li>如果 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>compareFunction(a, b)</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 返回一个<strong>正数</strong>，那么 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>b</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 会排在 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>a</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 的前面。</li> <li>如果 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>compareFunction(a, b)</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 返回<strong>0</strong>，那么 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>a</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 和 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>b</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 的相对位置保持不变（但要注意，并非所有<a >浏览器</a>都保证这一点，不过在V8引擎下通常是稳定的）。</li> </ul> <p>对于数字排序，最常见的写法是：</p> <img src=”https://img.php.cn/upload/article/001/221/864/175427352227818.png” alt=”js中如何对数组进行排序”><ul> <li> <strong>升序：</strong> <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>(a, b) => a – b</pre><div class=”contentsignin”></div></div><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>const numbers = [4, 2, 5, 1, 3]; numbers.sort((a, b) => a – b); console.log(numbers); // 输出: [1, 2, 3, 4, 5]</pre><div class=”contentsignin”></div></div></li> <li> <strong>降序：</strong> <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>(a, b) => b – a</pre><div class=”contentsignin”></div></div><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>const numbersDesc = [4, 2, 5, 1, 3]; numbersDesc.sort((a, b) => b – a); console.log(numbersDesc); // 输出: [5, 4, 3, 2, 1]</pre><div class=”contentsignin”></div></div></li> </ul> <p>值得一提的是，ES2023 引入了一个新的方法 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>toSorted()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div>，它与 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 类似，但它不会修改原始数组，而是返回一个新排序的数组。这在很多场景下非常有用，可以避免意外的副作用。</p><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>const originalNumbers = [4, 2, 5, 1, 3]; const sortedNumbers = originalNumbers.toSorted((a, b) => a – b); console.log(sortedNumbers); // 输出: [1, 2, 3, 4, 5] console.log(originalNumbers); // 输出: [4, 2, 5, 1, 3] (原数组未被修改)</pre><div class=”contentsignin”></div></div><h3>如何对包含数字或复杂对象的数组进行精确排序？</h3> <p>当数组中存放的不是简单的数字，而是字符串（需要按字母顺序，甚至考虑语言环境）、日期，或者更常见的，包含多个属性的复杂对象时，<div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 方法的比较函数就显得尤为重要了。</p> <p>对于字符串排序，尤其是需要考虑不同语言环境（比如中文拼音顺序、德语带音标的字符）时，使用 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>String.prototype.localeCompare()</pre><div class=”contentsignin”></div></div> 会比简单的 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”><</pre><div class=”contentsignin”></div></div> 或 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>></pre><div class=”contentsignin”></div></div> 运算符更靠谱。</p><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>const words = [‘réservé’, ‘déjà vu’, ‘café’, ‘apple’]; words.sort((a, b) => a.localeCompare(b, ‘fr’, { sensitivity: ‘base’ })); console.log(words); // 可能会根据locale输出 [‘apple’, ‘café’, ‘déjà vu’, ‘réservé’] 或其他顺序，取决于具体环境和选项</pre><div class=”contentsignin”></div></div><p><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>localeCompare</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 的第二个参数是语言标签（如 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>’en-US'</pre><div class=”contentsignin”></div></div>, <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>’zh-CN'</pre><div class=”contentsignin”></div></div>），第三个参数是选项对象，可以控制大小写敏感度、数字识别等。</p> <p>处理复杂对象数组的排序，通常是根据对象的一个或多个属性来决定顺序。假设我们有一个用户列表，需要按年龄排序，或者按姓名排序：</p><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>const users = [ { name: ‘Alice’, age: 30 }, { name: ‘Bob’, age: 25 }, { name: ‘Charlie’, age: 30 }, { name: ‘David’, age: 28 } ]; // 按年龄升序排序 users.sort((a, b) => a.age – b.age); console.log(users); /* [ { name: ‘Bob’, age: 25 }, { name: ‘David’, age: 28 }, { name: ‘Alice’, age: 30 }, { name: ‘Charlie’, age: 30 } ] */ // 如果年龄相同，则按姓名升序排序 users.sort((a, b) => { if (a.age !== b.age) { return a.age – b.age; } // 年龄相同，按姓名进行字符串比较 return a.name.localeCompare(b.name); }); console.log(users); /* [ { name: ‘Bob’, age: 25 }, { name: ‘David’, age: 28 }, { name: ‘Alice’, age: 30 }, // Alice 在 Charlie 前面 { name: ‘Charlie’, age: 30 } ] */</pre><div class=”contentsignin”></div></div><p>这种多条件排序的模式非常实用，它体现了比较函数的核心逻辑：优先比较最重要的条件，如果相等，则继续比较次要条件，以此类推。</p> <h3>排序时需要注意哪些常见陷阱和性能考量？</h3> <p>在使用 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>Array.prototype.sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 时，确实有一些地方容易踩坑，同时对于性能也需要有基本的认识。</p> <p>一个最大的陷阱就是前面提到的 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 方法<strong>会修改原数组</strong>。如果你不希望原始数据被改变，那么在调用 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 之前，你必须先创建一个数组的副本。最简单的方式是使用展开运算符 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>[…]</pre><div class=”contentsignin”></div></div> 或者 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>slice()</pre><div class=”contentsignin”></div></div> 方法：</p><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>const originalArray = [3, 1, 4]; const sortedCopy = […originalArray].sort((a, b) => a – b); // 或者 const sortedCopy = originalArray.slice().sort((a, b) => a – b); console.log(originalArray); // [3, 1, 4] console.log(sortedCopy); // [1, 3, 4]</pre><div class=”contentsignin”></div></div><p>ES2023 的 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>toSorted()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 方法就是为了解决这个痛点而生的，它直接返回一个新数组，避免了手动复制的麻烦。</p> <p>另一个常见问题是，如果你的数组中混杂了不同类型的数据（比如数字和字符串），并且你没有提供一个健壮的比较函数，那么 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 的行为可能会变得非常不可预测。它会尝试将所有元素都转换为字符串进行比较，这通常不是你想要的。所以，务必确保你的比较函数能正确处理所有可能的数据类型。</p> <p>关于<strong>稳定性</strong>：一个排序算法被称为“稳定”的，是指如果两个元素在排序前的相对顺序是 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>a</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 然后 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>b</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div>，且 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>a</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 和 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>b</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 在排序键上是相等的，那么排序后 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>a</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 仍然会在 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>b</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 的前面。JavaScript 的 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 方法的稳定性<strong>不是在所有浏览器和所有情况下都保证的</strong>。虽然现代浏览器（特别是基于V8引擎的chrome和Node.js）通常实现了稳定的排序（比如Timsort或MergeSort），但从规范层面来说，它并不强制要求稳定。这意味着，如果你依赖于相等元素的原始相对顺序，那么你需要自己额外处理，或者选择一个明确保证稳定性的库。</p> <p>在<strong>性能</strong>方面，<div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 方法的平均时间复杂度通常是 O(N log N)，这对于大多数数组来说都是非常高效的。N 是数组的元素数量。这个复杂度是比较理想的，因为它意味着随着数组规模的增长，排序所需的时间不会爆炸式增长。然而，一些因素会影响实际性能：</p> <ul> <li> <strong>比较函数的复杂性：</strong> 如果你的比较函数内部执行了大量计算、字符串操作（比如多次调用 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>localeCompare</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 或正则匹配），那么每次比较都会耗费更多时间，从而拖慢整个排序过程。尽量让比较函数保持简洁高效。</li> <li> <strong>数组大小：</strong> 尽管复杂度是 O(N log N)，但对于非常庞大的数组（例如数十万甚至上百万条记录），即使是高效的算法也需要一定时间。在这种极端情况下，你可能需要考虑在后端进行排序，或者在前端采用增量加载、虚拟列表等技术来优化用户体验，而不是一次性对所有数据进行排序。</li> <li> <strong>引擎实现：</strong> 不同的JavaScript引擎可能采用不同的排序算法，其具体性能表现也会有所差异，但通常都优化得很好。</li> </ul> <h3>除了基本的升序降序，还有哪些高级排序需求和实现方式？</h3> <p>除了简单的升序降序，实际开发中我们经常会遇到一些更复杂的排序场景。</p> <p><strong>1. 依据多个字段进行排序（多级排序）</strong> 这在处理表格数据或对象列表时很常见，比如“先按部门排序，部门相同再按年龄排序，年龄相同再按姓名排序”。我们已经在前面的例子中演示了这种模式：在比较函数中，首先判断第一个排序字段，如果它们不相等，就直接返回比较结果；如果相等，则继续比较下一个字段，直到找到差异或所有字段都比较完毕。</p><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>const employees = [ { name: ‘Bob’, dept: ‘HR’, age: 30 }, { name: ‘Alice’, dept: ‘IT’, age: 28 }, { name: ‘Charlie’, dept: ‘HR’, age: 25 }, { name: ‘David’, dept: ‘IT’, age: 28 } ]; employees.sort((a, b) => { // 部门升序 const deptCompare = a.dept.localeCompare(b.dept); if (deptCompare !== 0) { return deptCompare; } // 部门相同，按年龄升序 const ageCompare = a.age – b.age; if (ageCompare !== 0) { return ageCompare; } // 年龄也相同，按姓名升序 return a.name.localeCompare(b.name); }); console.log(employees); /* [ { name: ‘Charlie’, dept: ‘HR’, age: 25 }, { name: ‘Bob’, dept: ‘HR’, age: 30 }, { name: ‘Alice’, dept: ‘IT’, age: 28 }, { name: ‘David’, dept: ‘IT’, age: 28 } // 注意：如果JS引擎不保证稳定性，Alice和David的相对顺序可能互换 ] */</pre><div class=”contentsignin”></div></div><p><strong>2. 按照自定义顺序或映射值排序</strong> 有时，你可能需要按照一个非字母、非数字的特定逻辑顺序来排序，例如，将状态按照“待处理”、“进行中”、“已完成”、“已取消”这样的固定流程顺序排列。实现这种需求的一种常见方法是创建一个映射对象，将每个状态映射到一个数字，然后根据这个数字进行排序。</p><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>const statuses = [‘进行中’, ‘已完成’, ‘待处理’, ‘已取消’]; const statusOrder = { ‘待处理’: 1, ‘进行中’: 2, ‘已完成’: 3, ‘已取消’: 4 }; statuses.sort((a, b) => statusOrder[a] – statusOrder[b]); console.log(statuses); // 输出: [“待处理”, “进行中”, “已完成”, “已取消”]</pre><div class=”contentsignin”></div></div><p><strong>3. 对数组中的特定类型元素进行排序，同时保持其他元素的位置</strong> 这种情况比较少见，但如果遇到，通常的做法是先过滤出需要排序的元素，对其进行排序，然后将它们重新插入到原数组的正确位置，或者使用更复杂的自定义迭代和交换逻辑。不过，更推荐的做法是，如果可以，将所有元素都纳入排序范围，只是在比较函数中为不需要排序的元素定义一个“不移动”的逻辑（例如，让它们始终返回0）。</p> <p><strong>4. 使用第三方库</strong> 对于非常复杂的排序需求，或者为了代码的简洁性和一致性，很多开发者会选择使用成熟的第三方库，例如 Lodash。Lodash 的 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>_.sortBy()</pre><div class=”contentsignin”></div></div> 方法提供了非常灵活的排序能力，支持按多个属性排序、按自定义迭代器排序等。</p><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=’brush:javascript;toolbar:false;’>// 假设你已经安装并引入了 Lodash // import _ from ‘lodash’; const items = [ { name: ‘apple’, price: 10, category: ‘fruit’ }, { name: ‘banana’, price: 5, category: ‘fruit’ }, { name: ‘carrot’, price: 3, category: ‘vegetable’ } ]; // 按类别升序，然后按价格降序 const sortedItems = _.sortBy(items, [‘category’, (item) => -item.price]); console.log(sortedItems); /* [ { name: ‘banana’, price: 5, category: ‘fruit’ }, { name: ‘apple’, price: 10, category: ‘fruit’ }, { name: ‘carrot’, price: 3, category: ‘vegetable’ } ] */</pre><div class=”contentsignin”></div></div><p>使用库的好处是它们通常经过了大量的测试和优化，并且提供了更高级的抽象，可以减少我们自己编写复杂比较函数的负担。但对于大多数常规需求，JavaScript 原生的 <div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><div class=”code” style=”position:relative; padding:0px; margin:0px;”><pre class=”brush:php;toolbar:false”>sort()</pre><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div><div class=”contentsignin”></div></div> 配合自定义比较函数已经足够强大和灵活了。</p>

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