Javascript array filter child！

Question

The first array is as follows：

   var arr = [
  {
    key: 1,
    title: 'aa',
    children: [
      {
        key: 2,
        title: 'bb',
        children: [
          {
            key: 3,
            title: 'cc', 
            children: [
              {
                key: 5,
                title: 'ee', 
                children: [
                  {
                    key: 6,
                    title: 'ff'
                  },
                  {
                    key: 7,
                    title: 'gg'
                  },
                  {
                    key: 8,
                    title: 'hh'
                  }                  
                ]
              }
            ]
          },
          {
            key: 4,
            title: 'dd', 
          }          
        ]
      }    
    ]
  }
]
console.log(arr)

If the second array is as follows：

arr2 = [1, 2, 3, 4, 8]

Then I expect array 3 to be as follows：

arr3 = [4, 8]

Answer 1

您可以先获取路径，然后过滤给定的键（如果它大于两个路径），然后过滤出该值。

function filter(source, targets) {

    function getPath(array, target) {
        return array.reduce((r, { key, children }) => {
            var temp;
            if (key === target) return r.concat(key);
            if (children) {
                temp = getPath(children, target);
                if (temp.length) return r.concat(key, temp);
            }
            return r;
        }, [])
    }

    var temp = targets.map(k => getPath(source, k));
    return targets.filter(v => !temp.some((c => a => a.includes(v) && ++c)(-1)));
}

var array = [{ key: 1, title: 'aa', children: [{ key: 2, title: 'bb', children: [{ key: 3, title: 'cc', children: [{ key: 5, title: 'ee', children: [{ key: 6, title: 'ff' }, { key: 7, title: 'gg' }, { key: 8, title: 'hh' }] }] }, { key: 4, title: 'dd', }] }] }],
    result = filter(array, [1, 2, 3, 4, 8]);

console.log(result);