add github flavored heading anchors

anchorHeaders.js

// Hack to make intra-page links work
// replaces id's after angular strips them out 

/**
 * Given a Node, returns a 
 * GitHub flavored heading anchor
 * @param {Node}
 * @returns {string}
 */
function getHeadingAnchor(domNode) {
    var currentHeaderTextContent = domNode.textContent.trim();
    return currentHeaderTextContent.replace(/\W+/g, "-");
}

/**
 * Given a Node, adds a 
 * GitHub flavored heading anchor
 * @param {Node}
 */
function anchorHeadingNode(domNode) {
    try {
        var anchorText = getHeadingAnchor(domNode);
        domNode.setAttribute("id", anchorText);
    } catch (err) {
        if(!err) return;
        console.error(err);
    }
}

/**
 * Loops through Header 1-3 NodeList
 * and adds GitHub flavored heading anchor
 */
function anchorHeadingNodes() {
    var headersThatNeedID = "h1, h2, h3";
    var headerCollection = document.querySelectorAll(headersThatNeedID);

    for(var i=0; i < headerCollection.length; i++) {
        var currentHeader = headerCollection[i];
        anchorHeadingNode(currentHeader);
    }
}

// document.ready fires too soon
// must wait for external (angular) content to load
window.onload = anchorHeadingNodes;