在与ES6深度嵌套的javascript对象数组中查找值

In an array of objects I need to find a value -- where key is activity : However the activity key can be deeply nested in the array like so:

在一个对象数组中，我需要找到一个值 - 其中key是activity：但是，activity键可以深深嵌套在数组中，如下所示：

const activityItems = [
    {
        name: 'Sunday',
        items: [
            {
                name: 'Gym',
                activity: 'weights',
            },
        ],
    },
    {
        name: 'Monday',
        items: [
            {
                name: 'Track',
                activity: 'race',
            },
            {
                name: 'Work',
                activity: 'meeting',
            },
            {
                name: 'Swim',
                items: [
                    {
                        name: 'Beach',
                        activity: 'scuba diving',
                    },
                    {
                        name: 'Pool',
                        activity: 'back stroke',
                    },
                ],
            },
        ],    
    },
    {} ...
    {} ...
];

So I wrote a recursive algorithm to find out if a certain activity is in the array:

所以我编写了一个递归算法来查明某个活动是否在数组中：

let match = false;
const findMatchRecursion = (activity, activityItems) => {
    for (let i = 0; i < activityItems.length; i += 1) {
        if (activityItems[i].activity === activity) {
            match = true;
            break;
        }

        if (activityItems[i].items) {
            findMatchRecursion(activity, activityItems[i].items);
        }
    }

    return match;
};

Is there an ES6 way of determining if an activity exists in an array like this?

是否有ES6方法来确定这样的数组中是否存在活动？

I tried something like this:

我试过这样的事情：

const findMatch(activity, activityItems) {
    let obj = activityItems.find(o => o.items.activity === activity);
    return obj;
}

But this won't work with deeply nested activities.

但这不适用于深层嵌套的活动。

Thanks

谢谢

3 个解决方案

#1

You can use some() method and recursion to find if activity exists on any level and return true/false as result.

您可以使用some（）方法和递归来查找任何级别上是否存在活动，并返回true / false作为结果。

const activityItems = [{"name":"Sunday","items":[{"name":"Gym","activity":"weights"}]},{"name":"Monday","items":[{"name":"Track","activity":"race"},{"name":"Work","activity":"meeting"},{"name":"Swim","items":[{"name":"Beach","activity":"scuba diving"},{"name":"Pool","activity":"back stroke"}]}]}]

let findDeep = function(data, activity) {
  return data.some(function(e) {
    if(e.activity == activity) return true;
    else if(e.items) return findDeep(e.items, activity)
  })
}

console.log(findDeep(activityItems, 'scuba diving'))

#2

First, your function could be improved by halting once a match is found via the recursive call. Also, you're both declaring match outside, as well as returning it. Probably better to just return.

首先，通过递归调用找到匹配后暂停，可以改善您的功能。此外，你既要在外面宣布比赛，也要归还。回来可能更好。

const findMatchRecursion = (activity, activityItems) => {
    for (let i = 0; i < activityItems.length; i += 1) {
        if (activityItems[i].activity === activity) {
            return true;
        }

        if (activityItems[i].items && findMatchRecursion(activity, activityItems[i].items) {
            return true;
        }
    }

    return false;
};

There's no built in deep search, but you can use .find with a named function if you wish.

没有内置的深度搜索，但如果您愿意，可以将.find与命名函数一起使用。

var result = !!activityItems.find(function fn(item) {
  return item.activity === "Gym" || (item.items && item.items.find(fn));
});

#3

While not as elegant as a recursive algorithm, you could JSON.stringify() the array, which gives this:

虽然不如递归算法那么优雅，但你可以使用JSON.stringify（）数组，它给出了：

[{"name":"Sunday","items":[{"name":"Gym","activity":"weights"}]},{"name":"Monday","items":[{"name":"Track","activity":"race"},{"name":"Work","activity":"meeting"},{"name":"Swim","items":[{"name":"Beach","activity":"scuba diving"},{"name":"Pool","activity":"back stroke"}]}]}]

You could then use a template literal to search for the pattern:

然后，您可以使用模板文字来搜索模式：

`"activity":"${activity}"`

Complete function:

功能齐全：

findMatch = (activity, activityItems) =>
  JSON.stringify(activityItems).includes(`"activity":"${activity}"`);

const activityItems = [{
    name: 'Sunday',
    items: [{
      name: 'Gym',
      activity: 'weights',
    }, ],
  },
  {
    name: 'Monday',
    items: [{
        name: 'Track',
        activity: 'race',
      },
      {
        name: 'Work',
        activity: 'meeting',
      },
      {
        name: 'Swim',
        items: [{
            name: 'Beach',
            activity: 'scuba diving',
          },
          {
            name: 'Pool',
            activity: 'back stroke',
          },
        ],
      },
    ],
  }
];

findMatch = (activity, activityItems) =>
  JSON.stringify(activityItems).includes(`"activity":"${activity}"`);

console.log(findMatch('scuba diving', activityItems)); //true
console.log(findMatch('dumpster diving', activityItems)); //false

#1