Chrome tampermonkey helper for the elderly

contrastive.js

// ==UserScript==
// @name         Keyboard Shortcut Scripts
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Run scripts with keyboard shortcuts
// @match        *://*/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    function getRGB(color) {
        let rgb = color.match(/\d+/g);
        if (!rgb) return [255, 255, 255];
        return rgb.map(x => parseInt(x));
    }

    function getBrightness(rgb) { return (rgb[0] * 299 + rgb[1] * 587 + rgb[2] * 114) / 1000; }
    function darkenColor(rgb) { return rgb.map(x => Math.max(Math.floor(x / 2), 0)); }
    function rgbToString(rgb) { return `rgb(${rgb[0]}, ${rgb[1]}, ${rgb[2]})`; }

    function setDarkTextOnLightBackground() {
        document.querySelectorAll('*').forEach(el => {
            let color = window.getComputedStyle(el).color;
            let rgb = getRGB(color);
            if (getBrightness(rgb) < 200) {
                el.style.setProperty('color', rgbToString(darkenColor(rgb)), 'important');
            }
        });
    }

    document.addEventListener('keydown', function(e) {
        if (e.ctrlKey && e.shiftKey) {
            if (e.keyCode === 49) { // Key code for '1'
                document.querySelectorAll('*').forEach(el => {el.style.background = 'white'});
            } else if (e.keyCode === 50) {
                console.log('Executing Ctrl+Shift+2');
                setDarkTextOnLightBackground();
            }
        }
    });
})();