javascript translation of Benjamin Thomas' ruby code

javascript html truncate.js

/*
    truncate text within HTML
    does not work with malformed html
*/
function html_truncate(elem, num_words, truncate_string) {

    // local state
    var original = elem,
        current = elem.childNodes[0],
        count = 0;

    // traverse for text nodes
    while (current !== null) {

        // text node
        if (current.nodeType == 3) { // nodeType of 3 is text
            count += current.nodeValue.split(' ').length;
            // KLUDGE: figure out a way to remove leading/trailing whitespace
            if (count > num_words) {
                break;
            }
        }

        // walk over other nodes
        if (current.childNodes.length > 0) {
            current = current.childNodes[0];
        }
        else if (current.nextSibling !== null) {
            current = current.nextSibling;
        }
        else {
            var n = current;
            while (n.parentElement.nextSibling === null && n !== original) {
                n = n.parentElement;
            }
            if (n == original) {
                current = null;
            }
            else {
                current = n.parentElement.nextSibling;
            }
        }
    }

    // once the limit has been reached
    if (count >= num_words) {

        // truncate current text node
        var new_content = current.nodeValue.split(' ');
        new_content = new_content.slice(0, new_content.length - (count - num_words) + 1);

        // replace text
        if (current.nodeType === 3) {
            current.nodeValue = new_content.join(' ') + truncate_string;
        }

        // remove all succeeding nodes after limit
        while (current !== original) {
            while (current.nextSibling !== null) {
                current.nextSibling.parentElement.removeChild(current.nextSibling);
            }
            current = current.parentElement;
        }
    }
}

ruby code is here: http://benjaminthomas.org/2009-01-30/smart-html-truncate.html