some day i'll learn js. not today

 (function () {
    let src = data.element.mediaInfo && data.element.mediaInfo.source;
    if (!src) {
        setStatus('Quick Save: No media found');
        return;
    }

    // var domain = data.context.frameUrl.replace(/^(https?:\/\/)?([^@\n]+@)?(www\.)?(?:[^:\/\n?]+)/ig, '');

    var matches = data.context.frameUrl.match(/^https?\:\/\/([^\/?#]+)(?:[\/?#]|$)/i);
    var domain = matches && matches[1];
    domain = domain.replace(/[:/\\?!#*"<>]/ig, '');
    // var domain = data.context.frameUrl.replace(/^(?:https?:\/\/)?(?:[^@\n]+@)?(?:www\.)?([^:\/\n?]+)/ig, '')[1];
    // domain: /^(?:https?:\/\/)?(?:[^@\n]+@)?(?:www\.)?([^:\/\n?]+)/i

    // var fullurl = encodeURIComponent(data.context.frameUrl) + "/";

    // var pagetitle = document.title.replace(/[^a-zA-Z0-9-_]/g, '_');
    var pagetitle = document.title.replace(/[:/\\?!#*"<>|]/ig, '_');
    pagetitle = pagetitle.replace(/(^\([0-9]+\) )/g, '');
    pagetitle = pagetitle.replace(/ /g, '_');
    pagetitle = pagetitle.substr(0, 60);
    let placeholders = [], rules = [];

    // -- Define placeholders --
    placeholders.push([ '%MEDIADIR%', 'inbox/' + domain + "/" + pagetitle + "/"]);
    placeholders.push([ '%MISC%', 'misc/' + domain + "/" + pagetitle + "/"]);
    // placeholders.push([ '%AUDIO_DIR%', 'Audio/' ]);

    // -- Define rules --
    // Capturing group 1 must be the filename.
    // Defaults
    rules.push({ name: 'MEDIA', regex: /([^\/]+\.(gif|png|jpe?g|mp4|mkv|webm|flac|mp3|m4a|aac))($|\?|#)/i, target: '%MEDIADIR%/%F%' });
    rules.push({ name: 'MISC', regex: /(?=\w+\.\w{3,4}$).+/i, target: '%MISC%/%F%' });
    //rules.push({ name: 'MISC2', regex:/([^\/]+)($|\?|#)/i, target: '%MISC%/%F%' });
    // rules.push({ name: 'Video', regex: /([^\/]+\.(webm|mp4|mkv))($|\?|#)/i, target: '%VIDEO_DIR%/%F%' });
    // rules.push({ name: 'Audio', regex: /([^\/]+\.(mp3|flac|m4a|aac))($|\?|#)/i, target: '%AUDIO_DIR%/%F%' });


    // Evaluate rules
    let match = null;
    for (let i = 0; i < rules.length; i++) {
        if ((match = src.match(rules[i].regex)) != null) {
            // Evaluate placeholders
            let filename = match[1];
            placeholders.push([ '%F%', filename ]);
            let target = placeholders.reduce((target, placeholder) => target.replace(placeholder[0], placeholder[1]), rules[i].target);
            // data.context.frameUrl+"/"
            // -- Privileged operation begin --
            return executeInBackground((rule, src, target) => {
                // Start the download
                return browser.downloads.download({ url: src, filename: target }).then(id => {
                    if (rule.erase) {
                        // Remove the download from history on completion
                        let listener = (downloadDelta) => {
                            if ((downloadDelta.id === id) && (downloadDelta.state.current !== 'in_progress')) {
                                browser.downloads.onChanged.removeListener(listener);
                                browser.downloads.erase({ id: downloadDelta.id });
                            }
                        };
                        browser.downloads.onChanged.addListener(listener);
                    }
                });
            }, [ rules[i], src, target ])
            // -- Privileged operation end --
                .then(x => setStatus('Quick Save: SAVED! "' + filename + '" using ' + rules[i].name))
                .catch(err => setStatus('Quick Save: Failed to save "' + filename + ': ' + err + "\n pagetitle: " + pagetitle+ "\n domain: " + domain));
        } else {
            match = []
        }
    }

    setStatus('Quick Save: No matching rule');
    return;
}());