清理知乎页面。清理内容：首页推荐的短视频、问题页面的“盐选推荐”回答。

zhihu_cleaner.js

// ==UserScript==
// @name         Zhihu Cleaner
// @name:zh-CN   知乎界面清理
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://www.zhihu.com/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    const logging = true;
    const enabled = true;

    // create and return a closure
    const cleanerCreator = (selector) => {
        return (items) => {
            const ngItems = items.filter( item => item.querySelector(selector) );
            ngItems.forEach( item => {item.hidden = enabled;} );
            if (logging) {
                console.log(`ZHIHU CLEANER: ${ngItems.length}/${items.length} items cleaned (${selector})`);
            }
        }
    }

    // modified from https://greasyfork.org/zh-CN/scripts/35275-知乎-我不感兴趣/code, thanks!
    // listen on change events of a child list
    const registerHook = (parent, rmSelector) => {
        const cleaner = cleanerCreator(rmSelector);
        if (!parent.children) {
            setTimeout(() => {registerHook(parent, rmSelector);} , 500);
        }
        const ob = new MutationObserver((records) => {
            const addedItems = records.reduce((r, e) => r.concat([...e.addedNodes]), []);
            cleaner(addedItems);
        });
        ob.observe(parent, {childList: true});
        cleaner([...parent.children]);
    };

    // main page, remove zhihu short videos
    if (/.*www\.zhihu\.com\/?$/.test(location.href)) {
        const firstCard = document.querySelector("div.Card.TopstoryItem");
        registerHook(firstCard.parentElement, ".ZVideoItem");
    }

    // question page, remove ad answer by 盐选
    if (/.*www\.zhihu\.com\/question\/\d+$/.test(location.href)) {
        const yanxuanIDs = [ "zhujiangren" // 盐选推荐
                           , "yan-xuan-ke-pu-28" // 盐选科普
                           ];
        const yanxuan = yanxuanIDs.map(id => `meta[content="https://www.zhihu.com/people/${id}"]`);
        const firstAnswer = document.querySelector("div.List-item");
        registerHook(firstAnswer.parentElement, yanxuan);
    }
})();