How to create a dynamic html list with recursive function in Javascript (jQuery)

Question

I am trying to create an html list with a recursive function in javascript, but I really don't understand why the actual result doesn't match my expect result.

Json

{
    "sections": {
        "1": {
            "name": "Section 1",
            "sections": {
                "3": {
                    "name": "Section 1.1",
                    "sections": {
                        "4": {
                            "name": "Section 1.1.1",
                            "sections": {}
                        }
                    }
                }
            }
        },
        "2": {
            "name": "Section 2",
            "sections": {}
        }
    }
}

Javascript

$(document).ready(function() {
    generateHtml(myLoadedJson);
});

function generateHtml(pData) {
    var self = this;
    var html = '';
    if("sections" in pData) {
        html+= '<ul>';
        var objList = Object.keys(pData.sections);
        var nbr = objList.length;
        for(i=0; i<nbr; i++) {
            var key = objList[i];
            var obj = pData.sections[key];
            html+= '<li><div>' + obj.name + '</div>'
            html+= generateHtml(pData.sections[key]);
            html+= '</li>';
        }
        html+= '</ul>';
    }
    return html;
};

Expected result

<ul>
  <li>
    <div>Section 1</div> 
    <ul>
      <li>
        <div>Section 1.1<div>
        <ul>
          <li>
            <div>Section 1.1.1<div>
          </li>
        </ul>
      </li>
    </ul>
  </li>
  <li>
    <div>Section 2</div>
  </li>
</ul>

Actual result

<ul>
  <li>
    <div>Section 1</div>
    <ul>
      <li>
        <div>Section 1.1</div>
        <ul>
          <li>
            <div>section 1.1.1</div>
            <ul></ul>
          </li>
        </ul>
      </li>
    </ul>
  </li>
</ul>

Anyone have an idea?

Answer 1

The only mistake you have done is to use a global variable "i" in your loop.

for(i = 0; i < nbr; i++)

Instead, you should have written the statement as:

for(var i = 0; i < nbr; i++)

ensuring that you use a local variable for your loop.

You can see the working example using the following link

Answer 2

I think the problem is just in your for loop:

for(i = 0; i < nbr; i++)

should be:

for(var i=0; i<nbr; i++)

Essentially, all calls of the generateHtml(...) function are sharing the same loop variable (i). Therefore, when a sub-call increments i the calling loops i also increments. By adding var you ensure that each call has it's own local variable.