CODEWITHSUNDEEP
javascriptjquery
user5711656
user5711656

Reputation: 3678

how to count children in object in javascript?

I have a json array ..I want to refactor the json object ..but I am not able to make as expected output .I want to search all item or object and insert the children of parent ..I try like that

https://jsfiddle.net/nk6v0y36/1/

var new_Arry = [];
for (var i = 0; i < arry.length; i++) {
    var obj = {};
    var childeren = [];
    obj.con_id = arry[i].con_id;
    obj.children = [{
        con_to: arry[i].con_to
    }];
    new_Arry.push(obj)
}

console.log(new_Arry)

Expected output:

[{
    "con_id": 11,
    "children": [{
        "con_to": 12
    }]
}, {
    "con_id": 12,
    "children": [{
        "con_to": 13
    }, {
        "con_to": 14
    }]
}, {
    "con_id": 13,
    "children": []
}, {
    "con_id": 14,
    "children": [{
        "con_to": 15
    }]
}, {
    "con_id": 15,
    "children": [{
        "con_to": 16
    }]
}, {
    "con_id": 16,
    "children": []
}]

After answer

https://jsfiddle.net/nk6v0y36/7/

Answer not working..

Upvotes: 0

Views: 911

Answers (3)

Rebecka
Rebecka

Reputation: 1212

As thisOneGuy said, you are not checking if a con_id already exists in the new array, so for each element in the old array you are creating a corresponding new one. Your expected output though shows you want to merge these multiple con_id values into a single object.

You are also creating objects with con_to properties in the children arrays even when there is no such property, which again your expected output suggests you do not way.

One way to fix this would be:

var new_Arry = [];
var new_Hash = [];
for (var i = 0; i < arry.length; i++) {
    if (new_Hash[arry[i].con_id] === undefined ) {
        var obj = {
            con_id: arry[i].con_id,
            children: []
        };
        if( arry[i].con_to !== undefined ) {
            obj.children.push({ con_to: arry[i].con_to });
        }
        new_Hash[obj.con_id] = new_Arry.push(obj) - 1;
    } else if( arry[i].con_to !== undefined ) {
       new_Arry[new_Hash[arry[i].con_id]].children.push({ con_to: arry[i].con_to });
    }
}

console.log(new_Arry);

The key here is the new_Hash array, which uses the con_id value as its key, and stores the respective index in the new_Arry as its value.

So for each con_id in arry it first checks the new_Hash to see if there is an entry for it. If not then there is no entry in new_Arry, so it creates a new one.

Firstly the basic object, with con_id and a children array is created. It then checks whether there is a con_to property in arry, and only if there is does it add one as an object to the children array.

This object is then added to new_Arry and new_Hash updated so that an element for con_id references the new new_Arry index. As the .push() method returns extends an array and returns the new array length, the new index will always be this value minus one.

However if an entry for con_id was found in new_Hash then all you need to do it add the con_to value to the existing children array. Whilst presumably if there are multiple con_id entries in arry they must contain a con_to value, it also checks this just to be safe. The index number for the new_Arry as returned by new_Hash[arry[i].cond_id].

Incidentally, the reason for explicitly checking for undefined rather than seeing if value equates to true or false to check for its existence is a con_id or con_to value of 0 would be treated as false and skipped.

Upvotes: 1

thatOneGuy
thatOneGuy

Reputation: 10642

Here is the correct answer with the correct output : https://jsfiddle.net/nk6v0y36/4/

Basically you need to loop through your array to check if the con_id exists in that array, if it does, just add to children, if it doesnt add a new object.

var new_Arry = [];

for (var i = 0; i < arry.length; i++) {
  var obj = {};
  var childeren = [];
  if (new_Arry.length > 0) {
    console.log('start')
    console.log(new_Arry.length);

    var thisBool = false;
    for (var j = 0; j <= new_Arry.length; j++) {
      console.log('inside')
      if (new_Arry[j]) {
        if (new_Arry[j].con_id === arry[i].con_id) {
          console.log('has children')
          new_Arry[j].children[new_Arry[j].children.length] = {
            con_to: arry[i].con_to
          }
        } else {
        thisBool = true;
        }
      }
    }
    if(thisBool){
    obj.con_id = arry[i].con_id;
    obj.children = [{
      con_to: arry[i].con_to
    }];
    new_Arry.push(obj)
    }
  } else {
    console.log('no children')
    obj.con_id = arry[i].con_id;
    obj.children = [{
      con_to: arry[i].con_to
    }];
    new_Arry.push(obj)
  }
}

Check the output in the console log to see it's correct :)

Upvotes: 0

Adil Shaikh
Adil Shaikh

Reputation: 44740

Like this - 

var new_Arry = [];

for (var i = 0; i < arry.length; i++) {    
  var obj = {};
  var childeren = [];
  obj.con_id = arry[i].con_id;
  var child = [];
  var childrenObj = {};
  childrenObj.con_to = arry[i].con_to;
  child.push(childrenObj);
  obj.children = child;
  new_Arry.push(obj)
}

https://jsfiddle.net/nk6v0y36/3/

Upvotes: 0

Related Questions