Gets a text value of non-rendered (i.e. that have `display: none`) element (and it's childs). See more – https://stackoverflow.com/questions/52480730/replace-n-in-non-render-non-display-element-text

get-non-rendered-text-value.js

/**
 * Returns a text value of the element (and it's childs).
 *
 * @param dcmnt {Document}
 * The `document` where an element will be searched for.
 *
 * @param selector {string}
 * A selector by which will be search.
 *
 * @param separator {string}
 * A separator between the text of an different elements.
 * Defaults to `" "` (one space).
 *
 * @returns {string}
 * If the element was found, then it's text value, else an empty string.
 *
 * Warning!
 * 
 * This method is pretty slow, because it parse HTML slice,
 * not just gets a text value. It is necessary because of elements
 * that was not rendered (i.e. that have `display: none`).
 * `innerText` and `textContent` will return inappropriate result
 * for this kind elements.
 * For more see:
 *
 * @see https://stackoverflow.com/questions/52480730/replace-n-in-non-render-non-display-element-text
 */
function getTextValue(dcmnt, selector, separator) {
    separator = separator || " ";
    const element = dcmnt.querySelector(selector);

    if (!element) {
        return "";
    }

    /**
     * @see https://stackoverflow.com/questions/7394748/whats-the-right-way-to-decode-a-string-that-has-special-html-entities-in-it#7394787
     */
    const _decodeEntities = (html) => {
        const textArea = document.createElement("textarea");
        textArea.innerHTML = html;

        return textArea.value;
    };

    let innerHTML = element.innerHTML;

    // remove entities from HTML, but keep tags and other stuff.
    innerHTML = _decodeEntities(innerHTML);

    // replace HTML stuff with a space.
    // @see https://stackoverflow.com/questions/6743912/get-the-pure-text-without-html-element-by-javascript#answer-6744068
    innerHTML = innerHTML.replace(/<[^>]*>/g, " ");

    // replace multiple spaces with a single space.
    innerHTML = innerHTML.replace(/\s+/g, " ");

    // remove space from beginning and ending.
    innerHTML = innerHTML.trim();

    // for now there only one space between words.
    // so, we replace a space with the separator.
    innerHTML = innerHTML.replace(/ /g, separator);

    return innerHTML;
}