Creating a JSON Tree from a string hierarchy

Question

Given these 4 variables,

var el1 = {name:'ronaldo', team: 'europe/spain/realmadrid'}
var el2 = {name:'messi', team: 'europe/spain/barcelona'}
var el3 = {name:'gerald', team: 'europe/england/liverpool'}
var el4 = {name:'unknown english', team: 'europe/england'}

I need to produce this JSON tree hierarchy,

{
    "text":"europe",
    "leaf":false,
    "children":[
        {
            "text":"spain",
            "leaf":false,
            "children":[
                {
                    "text":"realmadrid",
                    "leaf":false,
                    "children":[
                        {
                            "text":"ronaldo",
                            "leaf":true
                        }
                    ]
                },
                {
                    "text":"barcelona",
                    "leaf":false,
                    "children":[
                        {
                            "text":"messi",
                            "leaf":true
                        }
                    ]
                }
            ]
        },
        {
            "text":"england",
            "leaf":false,
            "children":[
                {
                    "text":"unknown english",
                    "leaf":true
                },
                {
                    "text":"liverpool",
                    "leaf":false,
                    "children":[
                        {
                            "text":"gerald",
                            "leaf":true
                        }
                    ]
                }
            ]
        }
    ]
}

Jordan Reiter · Answer 1 · 2010-03-03T21:34:31.180

It'd be waaay easier if somehow el1-el4 were combined into a single object, like

var data = []
data[0] = {name:'ronaldo', team: 'europe/spain/realmadrid'}
data[1] = {name:'messi', team: 'europe/spain/barcelona'}
data[2] = {name:'gerald', team: 'europe/england/liverpool'}
data[3] = {name:'unknown english', team: 'europe/england'}

That way you can at least loop through them quickly when processing.

It'd also be useful to know why you need to have this stored as a JSON Tree. I mean, not all the nodes are the same kind of thing, right? The first level is continent, then country, then team name, and the leaves are individual soccer players. That's a fairly confusing data structure and I'm not sure how it would be useful. Either way, it may be more useful to translate it into a fielded structure first and then generate the tree.

Edit: Okay, so I thought about it a bit more and I think maybe something like this may do it.

var data = [];
data[0] = {name:'ronaldo', team: 'europe/spain/realmadrid'};
data[1] = {name:'messi', team: 'europe/spain/barcelona'};
data[2] = {name:'gerald', team: 'europe/england/liverpool'};
data[3] = {name:'unknown english', team: 'europe/england'};

var tree = {};
function fillTree(name,steps) {
   current = null;
   for (var y = 0; y < steps.length; y++) {
      if (y==0) {
         if (!tree.children||typeof tree.children == 'undefined'){
            tree = { text: steps[y], leaf: false, children: [] };
         }
         current = tree.children;
      } else {
         current.push({ text: steps[y], leaf: false, children: [] })
         current = current[current.length - 1].children;
      }
   }
   current.push({ text: name, leaf: true })
}

for (x=0; x < data.length; x++) {
  steps =data[x].team.split('/');
  fillTree(data[x].name,steps)
}

This creates a JavaScript object. I leave it to you to convert this to JSON.

Update:

Yeah, I see that the old script would have always put a record in at the second level even if it already existed. This is the new improved FillTree function:

var tree = {};
function fillTree(name,steps) {
   var current = null,
   existing = null,
   i = 0;
   for (var y = 0; y < steps.length; y++) {
      if (y==0) {
         if (!tree.children||typeof tree.children == 'undefined'){
            tree = { text: steps[y], leaf: false, children: [] };
         }
         current = tree.children;
      } else {
         existing = null;
         for (i=0; i < current.length; i++) {
            if (current[i].text === steps[y]) {
               existing = current[i];
               break;
            }
         }
         if (existing) {
            current = existing.children;
         } else {
            current.push({ text: steps[y], leaf: false, children: [] });
            current = current[current.length - 1].children;
         }
      }
   }
   current.push({ text: name, leaf: true })
}

The easiest way to convert this object into JSON, apparently, is to use JSON.stringify(tree) although apparently this is not uniformly supported (see the JavaScript JSON Page).

Thanks Jordan, but europe should only have 2 children (spain and england) — user275031, Feb 22 '10 at 02:50
@Dementic thanks! If you have a great solution yourself, please post it. — Jordan Reiter, Nov 07 '12 at 18:21
The code that I wrote takes the input given and exactly creates the output desired. The only difference is that it is output as a JavaScript structure, which the OP is free to convert to JSON using whatever method he or she desires. In case you were wondering, unconstructively criticizing someone else's answer is not a great way to get them motivated to answer one of your own questions. — Jordan Reiter, Nov 08 '12 at 17:22

score 0 · Answer 2 · edited May 23 '17 at 11:45

in case you agree to have children as object/hash instead of array, here is my solution based on Jordan's https://stackoverflow.com/a/2299268/214420

var el1 = {name:'ronaldo', team: 'europe/spain/realmadrid'}
var el2 = {name:'messi', team: 'europe/spain/barcelona'}
var el3 = {name:'gerald', team: 'europe/england/liverpool'}
var el4 = {name:'unknown english', team: 'europe/england'}

data = [el1,el2,el3,el4]
tree = {};
for(var i =0; i < data.length;i++){
    var steps = data[i].team.split('/'); 

    steps.push(data[i].name)
    var current = tree;

    for(var j = 0 ; j < steps.length;j++){
        var step = steps[j]
        current.leaf = false;
        current.children = current.children || {};
        current = current.children
        current[step] = current[step] || {text:step,leaf:true} 
        current = current[step];
    }
}

score 0 · Answer 3 · answered Feb 23 '15 at 13:55

Create your flat data array and than process on data for finding nested json

like

[{"itemname": "item1","settingkey": "key1","settingvalue": "value1"}, {"itemname": "item2","settingkey": "key2","settingvalue": "value2"},];

and then process this

var keys = Object.keys(dataMap);

var json = [];
for (var key in keys) {
        var innerJson = {};
        innerJson["name"] = keys[key];
        var innerMap = dataMap[keys[key]];

        if (innerMap instanceof Array) {
            innerJson["size"] = innerMap[0];
        } else if (innerMap instanceof Object) {

            var child = processHirarchiachalData(innerMap);
            innerJson["children"] = child;
        }
        json.push(innerJson);

}

Creating a JSON Tree from a string hierarchy

3 Answers3

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