从嵌套的对象数组中返回匹配项

Question

我有一组按 scheduleOn 数据分组的数组，如下所示

[{
scheduledOn: "2020-02-05T00:00:00"
matches:
{id: 1, homeTeamName: "BLUE", homeTeamId: 1, homeScore: 1, awayTeamName: "Red", awayTeamId: 2, …}
{id: 2,homeTeamName: "Red", homeTeamId: 2, homeScore: 1, awayTeamName: "Yellow", awayTeamId: 3, …}
},
{
scheduledOn: "2020-01-06T00:00:00"
matches:
0: {id:3, homeTeamName: "BLUE", homeTeamId: 1, homeScore: 0, awayTeamName: "Yellow", awayTeamId: 3, …}
}]

我想返回一个与所选 id 匹配的匹配对象（不是数组）

我尝试过的可能解决方案 1：

matches.map(match => match.matches
              .find(m => m.id === selectedId))

返回：

 [{

    id: 1, homeTeamName: "BLUE", homeTeamId: 1, homeScore: 1, awayTeamName: "Red", awayTeamId: 2, …
    }]

但我希望这只是一个对象而不是数组。

我尝试过的可能解决方案 2：

matches.map(match => match.matches
              .filter(m => m.id === selectedId))
              .map(match => console.log(match

)

返回：

 [
    {id: 1, homeTeamName: "BLUE", homeTeamId: 1, homeScore: 1, awayTeamName: "Red", awayTeamId: 2, …}
    ]

但这也作为数组返回。

有没有办法匹配 id 对象而不是数组？

感谢大家的帮助

Answer 1

你使用了两次find()

const matches = [{
scheduledOn: "2020-02-05T00:00:00",
matches:[
{id: 1, homeTeamName: "BLUE", homeTeamId: 1, homeScore: 1, awayTeamName: "Red", awayTeamId: 2 },
{id: 2,homeTeamName: "Red", homeTeamId: 2, homeScore: 1, awayTeamName: "Yellow", awayTeamId: 3 }]
},
{
scheduledOn: "2020-01-06T00:00:00",
matches:[{id:3, homeTeamName: "BLUE", homeTeamId: 1, homeScore: 0, awayTeamName: "Yellow", awayTeamId: 3 }]
}];


const selectedId =  3;
const required = matches.find(match => 
                  match.matches.find(m => m.id === selectedId));
console.log(required);

   // if you wanted nested object, add another `.find()`
   console.log(required .matches.find(m => m.id === selectedId));

Answer 2

您可以使用 flatMap() 将所有 matches 属性展平为单个数组并搜索：

const src = [{"scheduledOn":"2020-02-05T00:00:00","matches":[{"id":1,"homeTeamName":"BLUE","homeTeamId":1,"homeScore":1,"awayTeamName":"Red","awayTeamId":2},{"id":2,"homeTeamName":"Red","homeTeamId":2,"homeScore":1,"awayTeamName":"Yellow","awayTeamId":3}]},{"scheduledOn":"2020-01-06T00:00:00","matches":[{"id":3,"homeTeamName":"BLUE","homeTeamId":1,"homeScore":0,"awayTeamName":"Yellow","awayTeamId":3}]}],
      itemWithId2 = src.flatMap(({matches}) => matches).find(({id}) => id==2)
      
console.log(itemWithId2)      

不过，您应该记住，它在 Microsoft 浏览器中是 may fail（就像许多其他很酷的东西一样）（至少在 IE 消失之前）。

如果是这种情况，您可以使用arr.reduce((r,{matches}) => r.concat(matches), []) 而不是flatMap()。

不过，在处理大型数组时，@Zohaibljaz 建议的嵌套查找将是 more performant。

我的实现会是不可接受的不可读：

const src = [{"scheduledOn":"2020-02-05T00:00:00","matches":[{"id":1,"homeTeamName":"BLUE","homeTeamId":1,"homeScore":1,"awayTeamName":"Red","awayTeamId":2},{"id":2,"homeTeamName":"Red","homeTeamId":2,"homeScore":1,"awayTeamName":"Yellow","awayTeamId":3}]},{"scheduledOn":"2020-01-06T00:00:00","matches":[{"id":3,"homeTeamName":"BLUE","homeTeamId":1,"homeScore":0,"awayTeamName":"Yellow","awayTeamId":3}]}]

let objectHavingIdOf2 = {}

src.find(({matches}) => 
  matches.find(item => 
    item.id == 2 ? 
    (objectHavingIdOf2 = item, true) :
    false))
    
console.log(objectHavingIdOf2)    

Answer 3

这里有一个简单的递归函数可以帮助您：

function findById(arr, id) {
    return arr.find(a => {
        if (a.matches && a.matches.length > 0) {
            return a.id === id ? true : findById(a.matches, id)
        } else {
            return a.id === id
        }
    })
}

// call this method with your data
findById(data, 1)