sort json nested array based on index not working as expected

Question

I have a json array and I want to sort the array based on its index number

[  
   {  
      "name":"abc",
      "index":2,
      "values":[  
         {  
            "work":"three3",
            "index":3
         },
         {  
            "work":"one1",
            "index":1
         },
         {  
            "work":"two2",
            "index":2
         }
      ]
   },
   {  
      "name":"pqr",
      "index":1,
      "values":[  
         {  
            "work":"three",
            "index":3
         },
         {  
            "work":"two",
            "index":2
         },
         {  
            "work":"one",
            "index":1
         }
      ]
   }
]

What I expect from this array is:

[  
   {  
      "filename":"pqr",
      "children":[  
         {  
            "work":"one",
            "index":1
         },
         {  
            "work":"two",
            "index":2
         },
         {  
            "work":"three",
            "index":3
         }
      ]
   },
   {  
      "filename":"abc",
      "children":[  
         {  
            "work":"one1",
            "index":1
         },
         {  
            "work":"two2",
            "index":2
         },
         {  
            "work":"three3",
            "index":3
         }
      ]
   }
   ]

Tried something like below.

const filterBy = (arr, childname, filterText) =>
{
    return arr.map(({filename, children}) =>
    {
        return {filename, children: children.map(({filename, children}) =>
        {
           if (filename === childname)
               return {filename, children: children.filter(
                   x => x.filename.match(filterText)
               )};
           else
               return {filename, children};
        })};
    });
}

It is a json array and what we can not be sure it will be in order so I want an array or object should be in sorted order

But how can I include that index in inner level and outer level and sort using it accordingly?

brk · Accepted Answer · 2019-04-07 11:00:33Z

You can first sort the array based on index. This will return a sorted array now use map. Inside the callback function get the values array and again sort it.Inside the array map function return the object with required key and value

let data = [{
    "name": "abc",
    "index": 2,
    "values": [{
        "work": "three3",
        "index": 3
      },
      {
        "work": "one1",
        "index": 1
      },
      {
        "work": "two2",
        "index": 2
      }
    ]
  },
  {
    "name": "pqr",
    "index": 1,
    "values": [{
        "work": "three",
        "index": 3
      },
      {
        "work": "two",
        "index": 2
      },
      {
        "work": "one",
        "index": 1
      }
    ]
  }
]


let newdt = data.sort(function(a, b) {
  return a.index - b.index
}).map(function(item) {
  let val = item.values.sort(function(a, b) {
    return a.index - b.index;
  })

  return {
    name: item.name,
    children: val
  }
})
console.log(newdt)

RahulB · Accepted Answer · 2019-04-07 11:20:39Z

1

First sort the outer array, use same function to sort inner array

function compare(a, b) {
  if (a.index < b.index)
    return -1;
  if (a.index > b.index)
    return 1;
  return 0;
}

var objs = [{
    "name": "abc",
    "index": 2,
    "values": [{
        "work": "three3",
        "index": 3
      },
      {
        "work": "one1",
        "index": 1
      },
      {
        "work": "two2",
        "index": 2
      }
    ]
  },
  {
    "name": "pqr",
    "index": 1,
    "values": [{
        "work": "three",
        "index": 3
      },
      {
        "work": "two",
        "index": 2
      },
      {
        "work": "one",
        "index": 1
      }
    ]
  }
]


var result = objs.sort(compare).map(function(item) {
  var children = item.values.sort(compare);
  return {
    filename: item.name,
    children: children
  }
});

console.log(result);

edited Apr 7, 2019 at 11:20

answered Apr 7, 2019 at 11:05

RahulB

2,1101 gold badge21 silver badges28 bronze badges

2 Comments

brk Over a year ago

check expected & your output

brk Over a year ago

You can make the compare function more generic by passing the key by which it will be sorted. Assume it is not index key for bot the case then this compare function will fail

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