jellyfin-web/src/utils/url.ts

export const getWindowLocationSearch = (win?: Window | null | undefined) => {
    let search = (win || window).location.search;

    if (!search) {
        const index = window.location.href.indexOf('?');

        if (index != -1) {
            search = window.location.href.substring(index);
        }
    }

    return search || '';
};

export const getParameterByName = (name: string, url?: string | null | undefined) => {
    name = name.replace(/[[]/, '\\[').replace(/[\]]/, '\\]');
    const regexS = '[\\?&]' + name + '=([^&#]*)';
    const regex = new RegExp(regexS, 'i');
    const results = regex.exec(url || getWindowLocationSearch());

    if (results == null) {
        return '';
    }

    return decodeURIComponent(results[1].replace(/\+/g, ' '));
};