在object days中查找共性

Question

我有一个对象数组，我想找出它们之间最常见的连续日期，然后选择该连续日期对中的第一天。

let data = [
   {
     name: "mike",
     city: "Los Angeles",
     days: ["2020-01-02", "2020-01-03","2020-01-18", "2020-01-19"]
   },

   {
     name: "Kenny",
     city: "Chicago",
     days: ["2020-04-02", "2020-04-12","2020-04-19"]

   },
 
   {
     name: "James",
     city: "Los Angeles",
     days: ["2020-05-02", "2020-05-12","2020-05-19"]
   },
    {
     name: "Maggie",
     city: "Los Angeles",
     days: ["2020-11-12", "2020-11-13","2020-05-19"]
   },
   {
     name: "Ricardo",
     city: "Los Angeles",
     days: ["2020-01-02", "2020-01-03","2020-05-19"]
   },
   {
     name: "Reeny",
     city: "Chicago",
     days: ["2020-01-02", "2020-01-04","2020-05-09"]
   },

];

例如，对于洛杉矶，我想返回：

{
   city: "Los Angeles", 
   day: "2020-01-02",
   people: ["mike", "ricardo"],
}

"Maggie“不会出现，因为她连续可用的天数比Mike和James少。

对于迈克和詹姆斯来说，"2020-01-02"和"2020-01-03"出现在洛杉矶最多。

对于芝加哥，我只想返回一个空字符串，因为我没有任何连续的日期。

到目前为止，我遍历了数据并将城市推送到一个对象。如果城市已经在对象中，我将每个day推送到现有数组中。如果city不在散列对象中，那么我只需设置它并使其等于days

let obj = {};
data.forEach(x => {
   if (map[x.city]) {
       x.days.forEach(y => {
          map[x.city].push(y);
       })
   } else {
      map[x.city] = x.days;
   }
});

for (x in obj) {
    let arr = [...new Set(obj[x])]
    obj[x] = arr.sort();
}

我的结果是一个以城市为关键字的对象，值是天数(通过Set删除了重复项)：

obj = {
    "Los Angeles": ["2020-01-02", "2020-01-03","2020-01-18", "2020-01-19", "2020-05-02", "2020-05-12","2020-05-19", "2020-11-12", "2020-11-13"],
    "Chicago": ["2020-01-02", "2020-01-04","2020-04-02", "2020-04-12","2020-04-19", "2020-05-09"]
    }

从这一点来看，我不确定该怎么做。我想这是可以实现的，但我不知道下一步该怎么做。

Answer 1

您可以使用alasql https://github.com/agershun/alasql/wiki/Examples

使用alasql，你可以做: DISTINCT或GROUP等。

示例：

// Fill table with data
var person = [ 
    { name: 'bill' , sex:'M', income:50000 },
    { name: 'sara' , sex:'F', income:100000 },
    { name: 'larry' , sex:'M', income:90000 },
    { name: 'olga' , sex:'F', income:85000 },
];

// Do the query
var res = alasql("SELECT * FROM ? person WHERE sex='F' AND income > 60000", [person]);

document.getElementById("result").innerHTML = JSON.stringify(res);