Hello World,
Not a Fedora/Linux related topic so sorry if that pisses some of you off, but I am strongly considering adding a script to my browser to fix a youtube issue that has been driving me out of my mind!!!.. 
However since I know diddly about this stuff I thought I’d better try and ask can you guys pretty please check this code and let me know if this script is safe to use? 
And are there any lines I need to delete or modifications to make to stop it from updating itself without my knowledge or stuff like that?
Thank you very much in advance. 
// ==UserScript==
// @name YouTube Smaller Thumbnails
// @namespace http://greasyfork.org
// @version 0.0.6
// @description Adds additional thumbnails per row
// @author you
// @license MIT
// @match *://www.youtube.com/*
// @match *://youtube.com/*
// @run-at document-start
// @grant GM_registerMenuCommand
// @grant GM_unregisterMenuCommand
// @grant GM_addValueChangeListener
// @grant GM_getValue
// @grant GM_setValue
// @grant GM_deleteValue
// @require https://update.greasyfork.org/scripts/470224/1506547/Tampermonkey%20Config.js
// @downloadURL https://update.greasyfork.org/scripts/533610/YouTube%20Smaller%20Thumbnails.user.js
// @updateURL https://update.greasyfork.org/scripts/533610/YouTube%20Smaller%20Thumbnails.meta.js
// ==/UserScript==
(function() {
'use strict';
const DEFAULT_MAX_COLUMNS = 6; // Maximum amount of columns.
const DEFAULT_MAX_SHORTS_COLUMNS = 12; // Maximum amount of columns for shorts.
let cfg
if (
typeof GM_registerMenuCommand === 'undefined' ||
typeof GM_unregisterMenuCommand === 'undefined' ||
typeof GM_addValueChangeListener === 'undefined' ||
typeof GM_getValue === 'undefined' ||
typeof GM_setValue === 'undefined' ||
typeof GM_deleteValue === 'undefined'
) {
cfg = {
params: {
'columns': DEFAULT_MAX_COLUMNS,
'shortsColumns': DEFAULT_MAX_SHORTS_COLUMNS,
'shortsScale': 10,
'applyStyles': true
},
get: function (key) {
return typeof this.params[key] !== 'undefined' ? this.params[key] : null;
}
}
} else {
cfg = new GM_config({
columns: {
type: 'int',
name: 'Videos Per Row',
value: DEFAULT_MAX_COLUMNS,
min: 1,
max: 20
},
shortsColumns: {
type: 'int',
name: 'Shorts Per Row',
value: DEFAULT_MAX_SHORTS_COLUMNS,
min: 1,
max: 20
},
shortsScale: {
type: 'int',
name: 'Shorts Scale (in %)',
min: 10,
max: 200,
value: 10
},
applyStyles: {
type: 'boolean',
name: 'Apply Styles',
value: true
}
})
}
function debug(...args) {
console.log('%c[YouTube Smaller Thumbnails]', 'background: #111; color: green; font-weight: bold;', ...args)
}
function applyStyles() {
if (!cfg.get('applyStyles')) {
return
}
var style = document.createElement('style');
style.appendChild(document.createTextNode(`
ytd-rich-item-renderer[is-slim-media] {
width: ${cfg.get('shortsScale')}% !important;
}
`));
document.body.appendChild(style);
debug('Applied styles')
}
document.addEventListener("DOMContentLoaded", applyStyles);
document.addEventListener("load", applyStyles);
function installStyle(contents) {
var style = document.createElement('style');
style.innerHTML = contents;
document.body.appendChild(style);
}
function getTargetValue() {
return currentOrDefault(+cfg.get('columns'), DEFAULT_MAX_COLUMNS)
}
function getShortsTargetValue() {
return currentOrDefault(+cfg.get('shortsColumns'), DEFAULT_MAX_SHORTS_COLUMNS)
}
function currentOrDefault(value, defaultValue) {
const num = parseInt(value, 10);
if (!isNaN(num) && num.toString() === String(value).trim() && num > 0 && num < 100) {
return num
}
return defaultValue
}
function isShorts(itemElement) {
return null !== itemElement.getAttribute('is-slim-media')
}
function modifyGridStyle(gridElement) {
const currentStyle = gridElement.getAttribute('style');
if (!currentStyle) {
return;
}
const itemsPerRowMatch = currentStyle.match(/--ytd-rich-grid-items-per-row:\s*(\d+)/);
if (!itemsPerRowMatch) {
return;
}
const currentValue = parseInt(itemsPerRowMatch[1], 10);
if (isNaN(currentValue)) {
return;
}
const newValue = getTargetValue();
if (currentValue === newValue) {
return;
}
const newStyle = currentStyle.replace(
/--ytd-rich-grid-items-per-row:\s*\d+/,
`--ytd-rich-grid-items-per-row: ${newValue}`
);
gridElement.setAttribute('style', newStyle);
debug(`Modified items per row: ${currentValue} -> ${newValue}`);
}
function modifyItemsPerRow(itemElement) {
const currentValue = parseInt(itemElement.getAttribute('items-per-row'), 10);
if (isNaN(currentValue)) {
return;
}
const newValue = isShorts(itemElement) ?
getShortsTargetValue() :
getTargetValue();
if (currentValue === newValue) {
return;
}
itemElement.setAttribute('items-per-row', newValue);
debug(`Modified items per row: ${currentValue} -> ${newValue}`);
}
function modifyShortHidden(itemElement) {
if (!isShorts(itemElement)) {
return;
}
if (null === itemElement.getAttribute('hidden')) {
return
}
itemElement.removeAttribute('hidden');
debug(`Modified hidden`);
}
function modifyShelfRenderer(itemElement) {
const currentStyle = itemElement.getAttribute('style');
if (!currentStyle) {
return;
}
const itemsCountMatch = currentStyle.match(/--ytd-rich-shelf-items-count:\s*(\d+)/);
if (!itemsCountMatch) {
return;
}
const currentValue = parseInt(itemElement.getAttribute('elements-per-row'), 10);
if (isNaN(currentValue)) {
return;
}
const newValue = getShortsTargetValue()
if (currentValue === newValue) {
return;
}
const newStyle = currentStyle.replace(
/--ytd-rich-shelf-items-count:\s*\d+/,
`--ytd-rich-shelf-items-count: ${newValue}`
);
itemElement.setAttribute('style', newStyle);
itemElement.setAttribute('elements-per-row', newValue);
debug(`Modified elements per row: ${currentValue} -> ${newValue}`);
}
function processExistingElements() {
document.querySelectorAll('ytd-rich-grid-renderer').forEach(gridElement => {
modifyGridStyle(gridElement);
});
document.querySelectorAll('ytd-rich-item-renderer').forEach(itemElement => {
modifyItemsPerRow(itemElement);
modifyShortHidden(itemElement);
});
}
const observer = new MutationObserver((mutations) => {
mutations.forEach((mutation) => {
if (mutation.addedNodes && mutation.addedNodes.length > 0) {
mutation.addedNodes.forEach((node) => {
if (node.nodeType === Node.ELEMENT_NODE) {
if (node.tagName === 'YTD-RICH-GRID-RENDERER') {
modifyGridStyle(node);
}
if (node.tagName === 'YTD-RICH-ITEM-RENDERER') {
modifyItemsPerRow(node);
}
if (node.tagName === 'YTD-RICH-SHELF-RENDERER') {
modifyShelfRenderer(node);
}
node.querySelectorAll('ytd-rich-grid-renderer').forEach(gridElement => {
modifyGridStyle(gridElement);
});
node.querySelectorAll('ytd-rich-item-renderer').forEach(itemElement => {
modifyItemsPerRow(itemElement);
modifyShortHidden(itemElement);
});
node.querySelectorAll('ytd-rich-shelf-renderer').forEach(itemElement => {
modifyShelfRenderer(itemElement);
});
}
});
}
if (mutation.type === 'attributes') {
const target = mutation.target;
if (target.tagName === 'YTD-RICH-GRID-RENDERER' && mutation.attributeName === 'style') {
modifyGridStyle(target);
}
if (target.tagName === 'YTD-RICH-ITEM-RENDERER' && mutation.attributeName === 'items-per-row') {
if (mutation.attributeName === 'items-per-row') {
modifyItemsPerRow(target);
}
if (mutation.attributeName === 'hidden') {
modifyShortHidden(target);
}
}
if (target.tagName === 'YTD-RICH-SHELF-RENDERER' && mutation.attributeName === 'elements-per-row') {
modifyShelfRenderer(target);
}
}
});
});
function startObserver() {
processExistingElements();
observer.observe(document.documentElement, {
childList: true,
subtree: true,
attributes: true,
attributeFilter: ['style', 'hidden', 'items-per-row', 'elements-per-row']
});
debug('Observer started');
}
if (document.readyState === 'loading') {
document.addEventListener('DOMContentLoaded', startObserver);
} else {
startObserver();
}
setInterval(processExistingElements, 3000);
})();
And I’m guessing that if I take out the lines that “load”(is that even the right word?) that remote script then it won’t work anymore, or that they can’t even be taken out?
