Javascript for numbered table of contents

Question

I am putting together a Sharepoint wiki and on each article I have a wikipedia like table of contents from the headings using what I presume is a javascript that I found on the InterWebz.

<style>
#toc {
 display: table;
 border: 1px solid #aaa;
 background-color: #f9f9f9;
 font-size: 95%;
 padding: 7px;
}
#toc #tocHeader  {
 font-weight: bold;
 text-align: center;
}
#toc a:before { /* content:"• "; */ }
#toc a { line-height: 15px; margin: 10px; }
#toc .toc_Level1 { margin-left: 5px; }
#toc .toc_Level2 { margin-left: 15px; }
#toc .toc_Level3 { margin-left: 25px; }
#toc .toc_Level4 { margin-left: 35px; }
</style> 
<div id="toc"></div> 
<script src="https://code.jquery.com/jquery-1.12.3.min.js"></script>
<script type="text/javascript"> 
function GenerateTOC() {
  $("#toc").append('<p id="tocHeader">Contents</p>');
  $(".ms-rteElement-H1, .ms-rteElement-H1B, .ms-rteElement-H2, .ms-rteElement-H2B, .ms-rteElement-H3, .ms-rteElement-H3B, .ms-rteElement-H4, .ms-rteElement-H4B").each(function(i) {
 var currentNode = $(this);
  currentNode.attr("id", "title" + i);
 var linkClass = (currentNode.hasClass('ms-rteElement-H1') || currentNode.hasClass('ms-rteElement-H1B'))
   ? "toc_Level1" 
   : (currentNode.hasClass('ms-rteElement-H2') || currentNode.hasClass('ms-rteElement-H2B'))
   ? "toc_Level2" 
   : (currentNode.hasClass('ms-rteElement-H3') || currentNode.hasClass('ms-rteElement-H3B'))
   ? "toc_Level3" 
   : (currentNode.hasClass('ms-rteElement-H4') || currentNode.hasClass('ms-rteElement-H4B'))
   ? "toc_Level4" 
   : "";
  $("#toc").append("<a id='link'" + i + "' class='" + linkClass + "' href='#title" + i + "' title='" + currentNode.attr("tagName") + "'>" + currentNode.html() + "</a><br>");
  currentNode.append(" <a href='#tocHeader'>[top]</a>");
  });
}
_spBodyOnLoadFunctionNames.push('GenerateTOC');
</script>

My intention is to make the table of contents numbered separately for each level of indentation, e.g.:

1. Heading 1   
  1.1. Heading 2    
  1.2. Heading 2   
2. Heading 1
  2.1. Heading 2   
  2.2. Heading 2

Although I more or less understand what is happening in this code I have absolutely no knowledge of javascript (or web development for that matter - I have no idea how I got to what I am currently doing now to be honest), so I have very little idea how to implement it. I can see the function already has a counter to generate the internal link.

My strategy would be to put in two additional variables, say J and K (I have only two levels of indent), where J would increment only when it is level 1 heading (Element-H1, toc_Level1) and K would increment always but would get reset to 0 whenever level 1 heading (Element-H1, toc_Level1) is processed, however I have absolutely no idea how to make that happen.

EDIT:

I added the remaining parts of the javascript, however they only define the formatting of the table of contents, so I did not deem them relevant at first.

The website is structured as follows:

<span class="ms-rteElement-Name">NAME</span>
<hr/>
<span class="ms-rteElement-Section">Section1</span>
<hr/>
<span class="ms-rteStyle-Text">Stuff</span>
<p><span class="ms-rteElement-Section">Section2</span></p>
<hr/>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H1">Heading 1</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H2">Heading 2</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H2">Heading 2</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H1">Heading 1</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H2">Heading 2</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H2">Heading 2</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<span class="ms-rteElement-Section">Section3</span>
<hr/>
<p><span class="ms-rteStyle-Text">More fluff</span></p>

The script as given above generates the table of contents perfectly, just without the preceeding numbers of course.

Answer 1

So I have finally figured it out. Unfortunately none of the answers gave what was intended (one generated a ToC where the second level bullet missed also the corresponding higher level bullet and the hyperlink function was missing; the other was missing the numbering entirely).

The solution was to add additional variables under the GenerateTOC() function

 var j = 0, k = 0;

And then put in conditional counter and counter reset based on the value of the linkClass variable and put them in the single text variable

 linkClass == "toc_Level1"     
   ? (j++, k = 0)       
   : linkClass == "toc_Level2"       
   ? k++       
   : "";

 var l = k == 0 
   ? (String(j) + ". ")   
   : (String(j) + "." + String(k) + ". ");

The text variable then was added just in front of the "currentNode.html" in the line creating the ToC entry.

<script src="https://code.jquery.com/jquery-1.12.3.min.js"></script>    
<script type="text/javascript">    
function GenerateTOC() {    
 var j = 0, k = 0; // counters    

  $("#toc").append('<p id="tocHeader">Contents</p>');      
  $(".ms-rteElement-KD_Heading1, .ms-rteElement-KD_Heading2").each(function(i) {

 var currentNode = $(this);

  currentNode.attr("id", "title" + i);

 var linkClass = (currentNode.hasClass('ms-rteElement-KD_Heading1') || currentNode.hasClass('ms-rteElement-H1B'))    
   ? "toc_Level1"    
   : (currentNode.hasClass('ms-rteElement-KD_Heading2') || currentNode.hasClass('ms-rteElement-H2B'))    
   ? "toc_Level2"    
   : "";

 linkClass == "toc_Level1"     // runs the counters
   ? (j++, k = 0)       
   : linkClass == "toc_Level2"       
   ? k++       
   : "";

 var l = k == 0     // concatenates the counters
   ? (String(j) + ". ")       
   : (String(j) + "." + String(k) + ". ");

  $("#toc").append("<a id='link'" + i + "' class='" + linkClass + "' href='#title" + i + "' title='" + currentNode.attr("tagName") + "'>" + l + currentNode.html() + "</a><br>");    
  currentNode.append(" <a href='#tocHeader'>[top]</a>");    
  });    
}    
_spBodyOnLoadFunctionNames.push('GenerateTOC');    
</script>

Answer 2

A possible solution

function GenerateTOC() {
  $("#toc").append('<p id="tocHeader">Contents</p>');
  $(".ms-rteElement-H1, .ms-rteElement-H1B, .ms-rteElement-H2, .ms-rteElement-H2B, .ms-rteElement-H3, .ms-rteElement-H3B, .ms-rteElement-H4, .ms-rteElement-H4B").each(function(i) {
    var currentNode = $(this);
    currentNode.attr("id", "title" + i);
    var linkClass = (currentNode.hasClass('ms-rteElement-H1') || currentNode.hasClass('ms-rteElement-H1B')) ?
      "toc_Level1" :
      (currentNode.hasClass('ms-rteElement-H2') || currentNode.hasClass('ms-rteElement-H2B')) ?
      "toc_Level2" :
      (currentNode.hasClass('ms-rteElement-H3') || currentNode.hasClass('ms-rteElement-H3B')) ?
      "toc_Level3" :
      (currentNode.hasClass('ms-rteElement-H4') || currentNode.hasClass('ms-rteElement-H4B')) ?
      "toc_Level4" :
      "";
    $("#toc").append("<a id='link'" + i + "' class='" + linkClass + "' href='#title" + i + "' title='" + currentNode.attr("tagName") + "'>" + currentNode.html() + "</a><br>");
    currentNode.append(" <a href='#tocHeader'>[top]</a>");
  });

  // level 1
  $(".ms-rteElement-H1, .ms-rteElement-H1B").each(function(index, el) {
    $(this).html(index + '. ' + $(this).text());
    // level 2
    $('.ms-rteElement-H2, .ms-rteElement-H2B', this).each(function(idx, child) {
      $(this).html(index + '.' + idx + ' ' + $(this).text());
    });
  });
}

Answer 3

A solution that generates an ordered list, which should be able to work with deeper documents:

function levelClassName(level) {
  if (typeof level !== "number") {
    throw new Error("Wrong argument type");
  }

  return "ms-rteElement-H".concat(level.toString(10));
}

function elementLink(element) {
  return $("<li></li>").text($(element).text());
}

function generateTOC() {
  var level = 1, // list level
    tocList = $("<ol></ol>"), // top level list
    lastElement = tocList;

  $("#toc").append('<p id="tocHeader">Contents</p>');
  $("#toc").append(tocList);

  $("span").each(function(index, value) {
    // make a jQuery object out of current element once instead of doing it
    // every time I want to use it
    var element = $(value),
      newElement;

    if (element.hasClass(levelClassName(level))) { // same level
      newElement = elementLink(value);
      // append inside list tag or next to last tag if it isn't a list
      lastElement[lastElement.prop("tagName") === "OL" ?
        "append" :
        "after"](newElement);
      lastElement = newElement;
    } else if (element.hasClass(levelClassName(level + 1))) { // deeper
      newElement = elementLink(value);
      // make a new list tag for the deeper level
      lastElement.append($("<ol></ol>").append(newElement));
      lastElement = newElement;
      level += 1;
    } else if (level - 1 >= 1 && // shallower
      element.hasClass(levelClassName(level - 1))) {
      newElement = elementLink(value);
      lastElement // list element
        .parent().parent() // -> list (on same level) -> list element above
        .after(newElement);
      lastElement = newElement;
      level -= 1;
    }
  });
}

$(document).ready(generateTOC);

#toc {
  display: table;
  border: 1px solid #aaa;
  background-color: #f9f9f9;
  font-size: 95%;
  padding: 7px;
}

#toc #tocHeader {
  font-weight: bold;
  text-align: center;
}

#toc a:before {
  /* content:"• "; */
}

#toc a {
  line-height: 15px;
  margin: 10px;
}

#toc .toc_Level1 {
  margin-left: 5px;
}

#toc .toc_Level2 {
  margin-left: 15px;
}

#toc .toc_Level3 {
  margin-left: 25px;
}

#toc .toc_Level4 {
  margin-left: 35px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="toc"></div>
<span class="ms-rteElement-Name">NAME</span>
<hr/>
<span class="ms-rteElement-Section">Section1</span>
<hr/>
<span class="ms-rteStyle-Text">Stuff</span>
<p><span class="ms-rteElement-Section">Section2</span></p>
<hr/>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H1">Heading 1</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H2">Heading 2</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H2">Heading 2</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H1">Heading 1</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H2">Heading 2</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<p><span class="ms-rteElement-H2">Heading 2</span></p>
<p><span class="ms-rteStyle-Text">Fluff</span></p>
<span class="ms-rteElement-Section">Section3</span>
<hr/>
<p><span class="ms-rteStyle-Text">More fluff</span></p>

There is no code that makes links clickable. The best way to do that would be to give unique ids to every heading and then link to them in ToC.