如何在对象数组中获取具有唯一值的键？ (JavaScript)

Question

我有一个包含两个值的对象数组：{path: '/index', ip: '123.456.789'} 有些路径是相同的，IP 也是如此。一些重复，一些独特的组合。

对于每个唯一路径，我想要附加到该路径的不同 ip 的数量。因此，例如，可能有 15 个对象 path: '/index'，但该路径只有 4 个唯一的 ip。

简单来说，我想查找特定网站页面的独立访问者数量。

希望这是有道理的，非常感谢

编辑：

到目前为止，这是我生成非唯一视图的方法：

export const generateViews = (viewData: string): Map<string, number> => {
  const pathViewMap: Map<string, number> = new Map();
  const viewDataArray = viewData.split("\n");
  for (let i = 0; i < viewDataArray.length; i++) {
    const [path] = viewDataArray[i].split(" ");
    if (path) {
      if (pathViewMap.has(path)) {
        pathViewMap.set(path, pathViewMap.get(path) + 1);
      } else {
        pathViewMap.set(path, 1);
      }
    }
  }

  return pathViewMap;
};

对于上下文，输入是来自 paths/ips

列表的日志文件的字符串

编辑 2：

感谢 Peter Seliger，我已经能够想出我自己的解决方案：

const viewDataArray = viewData.split("\n").filter((item) => item);
  const arr: { path: string; ip: string }[] = viewDataArray.map(
    (line: string) => {
      const [path, ip] = line.split(" ");
      if (path && ip) {
        return { path, ip };
      }
    }
  );
  const paths: string[] = Array.from(new Set(arr.map((obj) => obj.path)));
  const uniqueViewsMap: Map<string, number> = new Map();

  for (let i = 0; i < paths.length; i++) {
    const path = paths[i];
    const ips = Array.from(
      new Set(arr.filter((obj) => obj.path === path).map((obj) => obj.ip))
    );
    uniqueViewsMap.set(path, ips.length);
  }

  console.log("==uniqueViewsMap==", uniqueViewsMap);

Answer 1

const sampleData = [
  { path: '/index', ip: '123.456.789' },
  { path: '/index/x', ip: '123.456.789' },
  { path: '/index/', ip: '123.456.78' },
  { path: '/index/y', ip: '123.456.789' },
  { path: '/index/', ip: '123.456.89' },
  { path: 'index/', ip: '123.456.9' },
  { path: 'index', ip: '123.456.8' },
  { path: '/index/', ip: '123.456.78' },
  { path: '/index/x/', ip: '123.456.78' },
  { path: 'index/x/', ip: '123.456.7' },
  { path: 'index/x', ip: '123.456.6' },
];
console.log(
  sampleData
    .reduce((result, { path, ip }, idx, arr) => {

      // sanitize/unify any path value
      path = path.replace(/^\/+/, '').replace(/\/+$/, '');

      // access and/or create a path specific
      // set and add the `ip` value to it.
      (result[path] ??= new Set).add(ip);

      // within the last iteration step
      // transform the aggregated object
      // into the final result with the
      // path specific unique ip count.      
      if (idx === arr.length - 1) {
        result = Object
          .entries(result)
          .reduce((obj, [path, set]) =>
            Object.assign(obj, {
              [path]: set.size
            }), {}
          );
      }
      return result;

    }, {})
);

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