MrMatt57/MrMatt.io

function TableOfContents() {
    var toc = "";
    var level = 2;

    var parseMatch = function(str, openLevel, id, titleText, closeLevel) {
        if (openLevel != closeLevel) {
            return str;
        }
        if (openLevel > level) {
            toc += (new Array(openLevel - level + 1)).join('<ul>');
        } else if (openLevel < level) {
            toc += (new Array(level - openLevel + 1)).join('</li></ul>');
        } else {
            toc += (new Array(level + 1)).join('</li>');
        } 
        level = parseInt(openLevel);
        var anchor = titleText.replace(/ /g, "_");
        toc += '<li><a href="#' + anchor + '">' + titleText +'</a>';
        return '<h' + openLevel + '><a href="#' + anchor + '" id="' + anchor + '">' +
            titleText + '</a></h' + closeLevel + '>';
    }

    var initToc = function() {
        var container = document.querySelector('#articlebody');
        var output = '#toc-content';
        container.innerHTML = container.innerHTML.replace(
            /<h([\d])(.*)>([^<]+)<\/h([\d])>/gi, function(str, openLevel, id, titleText, closeLevel) {
                return parseMatch(str, openLevel, id, titleText, closeLevel);
            });
    
        if (level) {
            toc += (new Array(level + 1)).join('</ul>');
        }
        document.querySelector(output).innerHTML += toc;
    }

    if(document.querySelectorAll('#toc').length > 0){
        initToc();
    }
};