JavaScript recursion find method

Question

I've the following JSON:

"params": [
            {
              "name": "a",
              "value": "tes",
              "isAttr": false,
              "children": [
                {
                  "name": "b",
                  "value": "b",
                  "isAttr": false,
                  "uid": "0.529892839025706",
                  "parent_uid": "0.8096382778603584",
                  "children": [],
                  "expanded": true,
                  "level": 2
                }
              ],
              "uid": "0.8096382778603584",
              "expanded": true,
              "level": 1
            },
            {
              "name": "c",
              "value": "c",
              "isAttr": false,
              "children": [
                {
                  "name": "d",
                  "value": "d",
                  "isAttr": false,
                  "children": [
                    {
                      "name": "e",
                      "value": "e",
                      "isAttr": false,
                      "children": [
                        {
                          "name": "f",
                          "value": "f",
                          "isAttr": false,
                          "uid": "0.5153285339474678",
                          "parent_uid": "0.646890748757869",
                          "children": [],
                          "expanded": false,
                          "level": 4
                        }
                      ],
                      "uid": "0.646890748757869",
                      "parent_uid": "0.2041493458673358",
                      "expanded": false,
                      "level": 3
                    }
                  ],
                  "uid": "0.2041493458673358",
                  "parent_uid": "0.9416675802785903",
                  "expanded": true,
                  "level": 2
                },
                {
                  "name": "g",
                  "value": "g",
                  "isAttr": false,
                  "children": [
                    {
                      "name": "h",
                      "value": "h",
                      "isAttr": false,
                      "uid": "0.3920950344763696",
                      "parent_uid": "0.6195112708956003",
                      "children": [],
                      "expanded": false,
                      "level": 3
                    }
                  ],
                  "uid": "0.6195112708956003",
                  "parent_uid": "0.9416675802785903",
                  "expanded": true,
                  "level": 2
                },
                {
                  "name": "i",
                  "value": "i",
                  "isAttr": false,
                  "children": [
                    {
                      "name": "j",
                      "value": "j",
                      "isAttr": false,
                      "children": [
                        {
                          "name": "k",
                          "value": "k",
                          "isAttr": false,
                          "children": [
                            {
                              "name": "l",
                              "value": "l",
                              "isAttr": false,
                              "uid": "0.009914681548252702",
                              "parent_uid": "0.68887914926745",
                              "children": [],
                              "expanded": false,
                              "level": 5
                            }
                          ],
                          "uid": "0.68887914926745",
                          "parent_uid": "0.8186752030160278",
                          "expanded": false,
                          "level": 4
                        }
                      ],
                      "uid": "0.8186752030160278",
                      "parent_uid": "0.8304482696112245",
                      "expanded": false,
                      "level": 3
                    },
                    {
                      "name": "m",
                      "value": "m",
                      "isAttr": false,
                      "children": [
                        {
                          "name": "n",
                          "value": "n",
                          "isAttr": false,
                          "uid": "0.25650549842976034",
                          "parent_uid": "0.14876524219289422",
                          "children": [],
                          "expanded": false,
                          "level": 4
                        }
                      ],
                      "uid": "0.14876524219289422",
                      "parent_uid": "0.8304482696112245",
                      "expanded": false,
                      "level": 3
                    }
                  ],
                  "uid": "0.8304482696112245",
                  "parent_uid": "0.9416675802785903",
                  "expanded": true,
                  "level": 2
                }
              ],
              "uid": "0.9416675802785903",
              "expanded": true,
              "level": 1
            }
          ]

I need a method that receive uid with the params and return the the specific item in the params with him parent. I did the following, but sometimes I got null in the found:

    var findItem = function(params, uid){
        if (!params)
            return null;

        for(var i = 0; i < params.length; i++){
            if(params[i].uid == uid)
                return params[i];
            else{

                findItem(params[i].children, uid);
            }
        }

        return null;
    }

example for getting null: passing uid for the b

Maybe there should be return findItem(params[i].children, uid); (you're missing the return)? EDIT: This is not exactly correct, please see my answer. — Roman Hocke
– Roman Hocke, Commented Apr 24, 2014 at 8:45

Roman Hocke · Accepted Answer · 2014-04-24 08:47:17Z

1

When You examine the children, You should check if You found something:

else {

    var found = findItem(params[i].children, uid);
    if (found !== null)
        return found;
}

answered Apr 24, 2014 at 8:47

Roman Hocke

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Павел Иванов · Accepted Answer · 2014-04-24 08:59:27Z

0

var findItem = function(params, uid){
    if (!params)
        return null;
    var res;
    for(var i = 0; i < params.length; i++){
        if(params[i].uid == uid)
            return params[i];
        else{
            res=findItem(params[i].children, uid);
        }
        if(res!=null) break;
    }
    return res;
};



findItem(params,"0.25650549842976034");

note that return in "for" loop cause breaking from loop, and also you should handle a result from recursive call (findItem(params[i].children, uid))

edited Apr 24, 2014 at 8:59

answered Apr 24, 2014 at 8:53

Павел Иванов

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