Highlighting and formatting code snippets using JavaScript

Question

I'm looking for a way to highlight and format code snippets passed as string for a live style guide. I'm playing around with highlighjs and prettify. They are really helpful and easy for highlighting, but I can't seem to figure out a way to format or whether they can actually do that or not.

By formatting, I mean tabs and newlines to make code legible. I need to pass code as a string to automate the output of dust template I'm using for the style guide.

That is, I want to pass:

"<table><tr><td class="title">Name</td><td class="title">Category</td><td class="title">Results</td></tr></table>"

And get something like:

<table>
        <tr>
            <td class="title">Name</td>
            <td class="title">Category</td>
            <td class="title">Results</td>
        </tr>
</table>

Any ideas on how to accomplish this? Thanks!

Mouser · Answer 1 · 2015-01-02T22:25:30.763

You could parse this as HTML into a DOM and than traverse every element writing it out and indenting it with every iteration.

This code will do the job. Feel free to use it and surely to improve it. It's version 0.0.0.1.

var htmlString = '<table><tr><td class="title">Name</td><td class="title">Category</td><td class="title">Results</td></tr></table>';

//create a containing element to parse the DOM.
var documentDOM = document.createElement("div");
//append the html to the DOM element.
documentDOM.insertAdjacentHTML('afterbegin', htmlString);

//create a special HTML element, this shows html as normal text.
var documentDOMConsole = document.createElement("xmp");
documentDOMConsole.style.display = "block";

//append the code display block.
document.body.appendChild(documentDOMConsole);

function indentor(multiplier)
{
    //indentor handles the indenting. The multiplier adds \t (tab) to the string per multiplication.
    var indentor = "";
    for (var i = 0; i < multiplier; ++i)
    {
        indentor += "\t";
    }
    return indentor;
}

function recursiveWalker(element, indent)
{
    //recursiveWalker walks through the called DOM recursively.
    var elementLength = element.children.length; //get the length of the children in the parent element.

    //iterate over all children.
    for (var i = 0; i < elementLength; ++i)
    {
        var indenting = indentor(indent); //set indenting for this iteration. Starts with 1.
        var elements = element.children[i].outerHTML.match(/<[^>]*>/g); //retrieve the various tags in the outerHTML.
        var elementTag = elements[0]; //this will be opening tag of this element including all attributes.
        var elementEndTag = elements[elements.length-1]; //get the last tag.

        //write the opening tag with proper indenting to the console. end with new line \n
        documentDOMConsole.innerHTML += indenting + elementTag + "\n"; 

        //get the innerText of the top element, not the childs using the function getElementText
        var elementText = getElementText(element.children[i]);

        //if the texts length is greater than 0 put the text on the page, else skip.
        if (elementText.length > 0)
        {
            //indent the text one more tab, end with new line.
            documentDOMConsole.innerHTML += (indenting + indentor(1) ) + elementText+ "\n";
        }

        if (element.children[i].children.length > 0)
        {
            //when the element has children call function recursiveWalker.
            recursiveWalker(element.children[i], (indent+1));
        }

        //if the start tag matches the end tag, write the end tag to the console.
        if ("<"+element.children[i].nodeName.toLowerCase()+">" == elementEndTag.replace(/\//, ""))
        {
            documentDOMConsole.innerHTML += indenting + elementEndTag + "\n";
        }
    }
}

function getElementText(el)
{
        child = el.firstChild,
        texts = [];

    while (child) {
        if (child.nodeType == 3) {
            texts.push(child.data);
        }
        child = child.nextSibling;
    }

    return texts.join("");
}

    recursiveWalker(documentDOM, 1);

http://jsfiddle.net/f2L82m8h/

Highlighting and formatting code snippets using JavaScript

1 Answers1