Coding4Fun-Facebook動態消息精簡化顯示

// ==UserScript==

// @name       Facebook動態消息精簡化顯示

// @namespace  http://blog2.darkthread.net/

// @version    0.9

// @description  隱藏動態消息頁面的間接訊息（說讚、回應、被標註），只顯示64字元摘要，但可視需要展開原文

// @match      https://www.facebook.com/

// @copyright  2015+, Jeffrey Lee

// ==/UserScript==

//REF：http://stackoverflow.com/questions/15329167/closest-ancestor-matching-selector-using-native-dom

//模擬jQuery.closest()

function closest(elem, selector) {

    var matchesSelector = elem.matches || elem.webkitMatchesSelector || 

                          elem.mozMatchesSelector || elem.msMatchesSelector;

    while (elem) {

        if (matchesSelector.bind(elem)(selector)) {

            return elem;

        } else {

            elem = elem.parentElement;

        }

    }

    return false;

}

//取得頁面總長

function getDocHeight() {

    return document.documentElement.scrollHeight;

}

var lastLen = getDocHeight();

//隱藏元素，取得64個字元作為摘要，並提供展開功能

//PS：此段很脆弱，一旦FB修改DOM格式就會失效

function hidePost(elem) {

    var content = elem.parentElement.parentElement.parentElement

                  .nextElementSibling.nextElementSibling;

    var friend = content.querySelector("h6").innerText.replace(/\n/g, "");

    var abstract = content.querySelector(".userContent").innerText;

    if (abstract.length > 64) abstract = abstract.substr(0, 64) + "...";

    abstract = abstract.replace(/\n/g, " ");

    var spn = document.createElement("a");

    spn.innerText = friend + " - " + abstract;

    spn.onclick = function() { 

        content.style.display = "";

        spn.remove();

        //更新頁面長度

        lastLen = getDocHeight();

    };

    elem.parentElement.appendChild(spn);

    content.style.display = "none";

}

var busy = false;

setInterval(function() {

    //長度未改變時不動作

    if (getDocHeight() == lastLen || busy) return;

    busy = true; //防止重覆執行

    var ary = document.querySelectorAll(

        "div[id^=topnews_main_stream] h5 span.fcg:not([data-shrink])");

    for (var i = 0; i < ary.length; i++) { 

        ary[i].setAttribute("data-shrink", "Y"); //處理完畢加上註記

        var t = ary[i].innerText;

        if (t.indexOf("說這個讚") > -1 || t.indexOf("被標註") > -1 || 

            t.indexOf("回應了") > -1) 

            hidePost(ary[i]);

    }    

    //移除推薦貼文

    ary = document.querySelectorAll("div[id^=topnews_main_stream] ._5g-l");

    for (var i = 0; i < ary.length; i++) {

        closest(ary[i], ".userContentWrapper").innerText = ary[i].innerText;

    }

    lastLen = getDocHeight();

    busy = false;

}, 3*1000);