Function _highlightCodeBlocks

src/rainbow.js:203–233

* Browser Only - Sends messages to web worker to highlight elements passed * in * * @param {Array} codeBlocks * @param {Function} callback * @return {void}

(codeBlocks, callback)

 * @return {void}
 */
function _highlightCodeBlocks(codeBlocks, callback) {
    const waitingOn = { c: 0 };
    for (const block of codeBlocks) {
        const language = getLanguageForBlock(block);
        if (block.classList.contains('rainbow') || !language) {
            continue;
        }

        // This cancels the pending animation to fade the code in on load
        // since we want to delay doing this until it is actually
        // highlighted
        block.classList.add('loading');
        block.classList.add('rainbow');

        // We need to make sure to also add the loading class to the pre tag
        // because that is how we will know to show a preloader
        if (block.parentNode.tagName === 'PRE') {
            block.parentNode.classList.add('loading');
        }

        const globalClass = block.getAttribute('data-global-class');
        const delay = parseInt(block.getAttribute('data-delay'), 10);

        ++waitingOn.c;
        _messageWorker(_getWorkerData(block.innerHTML, { language, globalClass, delay }), _generateHandler(block, waitingOn, callback));
    }

    if (waitingOn.c === 0) {
        callback();
    }
}

function _addPreloader(preBlock) {
    const preloader = document.createElement('div');