Filter keywords on Google+ webpage and hide corresponding posts

googleminus.js

/*
 * Filter keywords on Google+ webpage and hide corresponding posts
 * Notice that current filtering mechanism is VERY ROUGH
 * Use with caution
 */

/**
 * A keyword configuration
 * @param {String} keyword
 * @param {String} filtering_mode
 * @param {String} param
 * @constructor
 */
function KeywordConfig(keyword, filtering_mode, param) {
    this.keyword = keyword;
    this.filtering_mode = filtering_mode;
    this.param = param
}

const FILTERING_MODES = ["all_out", "blacken_keywords"];
const DEFAULT_FILTERING_MODE = "all_out";

/**
 * Append one array to another
 * @param  {Array} arr1 Array to be appended
 * @param  {Array} arr2 Array appended
 */
function my_append(arr1, arr2) {
	for (var i = 0 ; i < arr2.length ; ++i) {
		arr1.push(arr2[i]);
	}
}

/**
 * Whether one string contains another substring
 * @param  {String} str1 The string
 * @param  {String} str2 Substring
 * @return {boolean}
 */
function my_contains(str1, str2) {
	return str1.indexOf(str2) > -1;
}

/**
 * Whether a post div contains keyword
 * @param   {Array} keywords
 * @param   {HTMLDivElement} post_div
 * @returns {String} keyword being caught
 */
function scrutinize_post_div(keywords, post_div) {
	for (var i = 0 ; i < keywords.length ; ++i) {
		var keyword = keywords[i];
		if (my_contains(post_div.outerText, keyword)) {
			return keyword;
		}
	}
	return null;
}

/**
 * Wipe the post div out of stream completely
 * @param {HTMLDivElement} post_div
 * @param {String} keyword
 * @param {String} param
 */
function all_out(post_div, keyword, param) {
    post_div.innerHTML = "<div>Filtered " + build_black_cover(keyword) + "</div>";
}

/**
 * Replace keyword with black square in post div
 * @param {HTMLDivElement} post_div
 * @param {Array} keyword
 * @param {String} param
 */
function blacken_keywords(post_div, keyword, param) {
    var regex = new RegExp(keyword, "g");
    var replacement = (param === "") ? build_black_cover(keyword) : param;

    // Replace the keyword
    var raw_html = post_div.innerHTML;
    post_div.innerHTML = raw_html.replace(regex, replacement);
}

/**
 * Build a span with keyword blacked out but still visible when on hover
 * @param {String} keyword
 * @returns {string} raw html for the span
 */
function build_black_cover(keyword) {
    var replacement = new Array(keyword.length + 1).join("█");
    return "<span title='" + keyword + "'>" + replacement + "</span>";
}

function auto_ignore(post_div, keyword, param) {
    // TODO: simulate click
    var options_span = post_div.getElementsByClassName(POST_OPTIONS_SPAN_CLASS_NAME)[0];
    options_span.click();
}

/**
 * Vulnerable class names
 */
const STREAM_DIV_CLASS_NAME = "pga";
const POST_DIV_CLASS_NAME = "Yp yt Xa";
const ON_HOVER_POST_DIV_CLASS_NAME = "Yp yt Xa va";
const POST_OPTIONS_SPAN_CLASS_NAME = "d-s xw if";

/**
 * Main function
 * @param {Array} keyword_configs
 */
function filter(keyword_configs) {
    // Find stream div
    var stream_div = document.getElementsByClassName(STREAM_DIV_CLASS_NAME)[0];

    // Find post divs
    var post_divs = stream_div.getElementsByClassName(POST_DIV_CLASS_NAME);
    var on_hover_post_divs = stream_div.getElementsByClassName(ON_HOVER_POST_DIV_CLASS_NAME);

    // Add all post divs
    var all_post_divs = [];
    my_append(all_post_divs, post_divs);
    my_append(all_post_divs, on_hover_post_divs);

    // Filter
    var keyword_set = keyword_configs.map(function(config) {
        return config.keyword;
    });
    all_post_divs.forEach(function (post_div) {
        var keyword_caught = scrutinize_post_div(keyword_set, post_div);
        if (keyword_caught !== null) {
            var config_caught = keyword_configs.filter(function(config) {
                return config.keyword === keyword_caught;
            })[0];
            var filtering_mode_caught = config_caught.filtering_mode;
            var param_caught = config_caught.param;
            console.log("[googleminus] Caught " + keyword_caught + ", executing mode " + filtering_mode_caught);
            window[filtering_mode_caught](post_div, keyword_caught, param_caught);
        }
    })
}