Script for downloading Facebook videos

facebook-video-download-script.js

var LINK_TYPE_SD = 'sd_src_no_ratelimit';
var LINK_TYPE_HD = 'hd_src_no_ratelimit';

(function downloadVideo(type) {
    function getMyObject(doc) {
        var scriptsCollection = doc.getElementsByTagName("script");
        var scripts = [];
        var regExp = /video_ids/i;
        for (var i = scriptsCollection.length - 1; i >= 0; i--) {
            var script = scriptsCollection[i].innerHTML;
            if (regExp.test(script)) {
                scripts.push(script);
            };
        };

        var videoData = scripts[0].match(/"?videoData"?:(\[\{[^}]*\}\])/g).map(function(d) {
            return eval(d.match(/"?videoData"?:(\[\{[^}]*\}\])/)[1])[0];
        });

        var paramsObject = {
            videoData: videoData
        }
        return {
            paramsObjects: [paramsObject],
        };
    };

    function getDownloadLink(doc, video_id, type) {
        var myObject = getMyObject(doc);
        var dwLinks = myObject.paramsObjects[0].videoData.filter(function(video){return video.video_id == video_id;})[0];
        return dwLinks[type];
    };

    function download(type) {
        var videoId = document.location.href.match(/https?:\/\/www\.facebook\.com\/[^/]+\/videos\/([^/]+)/)[1];
        var link = getDownloadLink(document, videoId, type);

        var a = document.createElement('a');
        a.href = link;
        a.setAttribute('download', 'download');
        a.click();
    };

    return download(type);
})(LINK_TYPE_SD);