.js

// ==UserScript==
// @name         YouTube Subscriptions Filter
// @namespace    https://unascribed.com/
// @version      0.1
// @description  allows you to filter your YouTube subscription feed
// @author       Aesen "unascribed" Vismea
// @require      http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js
// @match        https://www.youtube.com/feed/subscriptions
// @match        http://www.youtube.com/feed/subscriptions
// ==/UserScript==

var filters = [
    {
        name: "Example Filter", // for informational purposes, can be omitted
        channel: "MrExample", // can also be a regex or a function
        title: /Minecraft$/, // ends with "Minecraft"
        action: "remove" // remove the video from the feed outright
    },
    {
        name: "Example Filter #2",
        title: /^Street Fighter/, // starts with "Street Fighter"
        action: "obscure" // replace the thumbnail with gray stripes
    }
];

function matches(filter, str) {
    if (!filter) {
        return true;
    } else if (filter instanceof RegExp) {
        return !!filter.exec(str);
    } else if (typeof filter === "string" || filter instanceof String) {
        return filter === str;
    } else if (typeof filter === "function") {
        return !!filter(str);
    } else {
        throw new Error("unknown filter type");
    }
}

function forEachInterruptible(arr, fun) {
    for (var i = 0; i < arr.length; i++) {
        if (!fun(arr[i])) return;
    }
}

$("div.yt-lockup-video > div.yt-lockup-dismissable").each(function(i, e) {
    e = $(e);
    var title = e.find("h3.yt-lockup-title > a").text();
    var channel = e.find("div.yt-lockup-byline > a").text();
    forEachInterruptible(filters, function(filter) {
        if (matches(filter.channel, channel) && matches(filter.title, title)) {
            switch (filter.action) {
                case "remove":
                    console.log("Removing video "+title+" by "+channel+(filter.name ? " (matches filter '"+filter.name+"')" : ""));
                    e.parent().parent().remove();
                    return false;
                case "obscure":
                    console.log("Obscuring thumbnail for video "+title+" by "+channel+(filter.name ? " (matches filter '"+filter.name+"')" : ""));
                    var thumb = e.find(".yt-thumb");
                    var img = thumb.find("img").remove();
                    thumb.css("width", img.attr("width")+"px");
                    thumb.css("height", img.attr("height")+"px");
                    img.remove();
                    thumb.css("background", "repeating-linear-gradient(45deg, #222, #222 10px, #444 10px, #444 20px)");
                    return false;
                default:
                    console.warn("Unknown filter action "+filter.action+(filter.name ? " (filter '"+filter.name+"')" : ""));
                    break;
            }
        }
        return true;
    });
});