如何依据sort_based_on_this_order数组排序JSON数组attachments？

我需要将名为attachments的JSON数组，按照sort_based_on_this_order数组指定的顺序排序。其中sort_based_on_this_order的元素对应attachments中每个对象filename字段里的13位数字后缀。

相关数组定义如下：

var sort_based_on_this_order = ['1666432801510', '1666434048280', '1666433926644', '1666434169913', '1666433101760', '1666434194815', '1666432849037', '1666432764144', '1666432044571', '1666432742444']
var attachments = [
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978911/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666433926644.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978911
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978910/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666434169913.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978910
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978909/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666434048280.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978909
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978907/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666433101760.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978907
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978905/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666434194815.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978905
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978904/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666432849037.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978904
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978903/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666432801510.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978903
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978902/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666432764144.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978902
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978901/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666432044571.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978901
                },
                {
                    "download_small_url": "https://kf.kobotoolbox.org/api/v2/assets/ajDWYWQoe9Gw6WAnK8H4fG/data/194338021/attachments/82978900/",
                    "mimetype": "image/jpeg",
                    "filename": "deploymentsmaster/attachments/a46854ceb37c4e55b4a2c5ea565c4ebf/04ac3197-7d0f-4301-bbaf-68daaee2b1a8/1666432742444.jpg",
                    "instance": 194338021,
                    "xform": 740320,
                    "id": 82978900
                }
            ]

我尝试了以下代码，但未能实现正确排序：

attachments.sort.forEach(zz => {
                return zz["filename"].match(/\b[0-9]{13}(?=\.[^.]+$)/)
            })

解决方案 #

错误原因

你使用了attachments.sort.forEach，这是错误的用法：sort是数组的排序方法，需要传入比较函数来定义排序规则，而不是用forEach遍历数组。

基础实现版本

// 从filename中提取13位数字后缀
function extractSuffix(filename) {
  const matchResult = filename.match(/\b[0-9]{13}(?=\.[^.]+$)/);
  return matchResult ? matchResult[0] : '';
}

// 执行排序
attachments.sort((itemA, itemB) => {
  const suffixA = extractSuffix(itemA.filename);
  const suffixB = extractSuffix(itemB.filename);
  // 比较两个后缀在排序数组中的索引位置
  return sort_based_on_this_order.indexOf(suffixA) - sort_based_on_this_order.indexOf(suffixB);
});

这段代码的逻辑：

1. 通过正则从每个附件的filename中提取对应的13位数字后缀
2. 使用indexOf获取后缀在sort_based_on_this_order中的位置
3. 根据索引差值排序：差值为负则itemA排在itemB前，正则相反，完全匹配指定的排序顺序

性能优化版本

如果数组元素较多，indexOf每次遍历数组会影响性能，建议提前创建后缀到索引的映射：

// 创建后缀-索引映射表，将O(n)查找转为O(1)
const suffixIndexMap = sort_based_on_this_order.reduce((map, suffix, index) => {
  map[suffix] = index;
  return map;
}, {});

// 提取后缀的函数不变
function extractSuffix(filename) {
  const matchResult = filename.match(/\b[0-9]{13}(?=\.[^.]+$)/);
  return matchResult ? matchResult[0] : '';
}

// 执行排序
attachments.sort((itemA, itemB) => {
  const suffixA = extractSuffix(itemA.filename);
  const suffixB = extractSuffix(itemB.filename);
  // 无匹配项默认放到数组末尾
  const indexA = suffixIndexMap[suffixA] ?? sort_based_on_this_order.length;
  const indexB = suffixIndexMap[suffixB] ?? sort_based_on_this_order.length;
  return indexA - indexB;
});

这个版本额外处理了无匹配后缀的情况，将这类附件自动放到排序后的数组末尾，同时大幅提升了排序效率。

内容的提问来源于stack exchange，提问作者Code Guy