Greasemonkey script to repeatedly refresh a given page, look for specific "Add to Cart" buttons, click them if present, and make a lot of noise on success.

readme.md

Add Items to Cart

Greasemonkey script to repeatedly refresh a given page, look for specific "Add to Cart" buttons, click them if present, and make a lot of noise on success.

This script was concieved and created due to the Nintendo Switch shortage during the COVID-19 pandemic. Its original purpose was to monitor for the Nintendo Switch console to come back into stock and get it added to your cart as quickly as possible. Granted, you stand very little chance compared to scalpers using fully automated tools like Bird Bot.

Installation

• Install Tampermonkey or Greasemonkey for your browser.
• Install the script into your browser by clicking the "Raw" button in the top-right corner of the js script below.

Setup

• Sign into your Amazon.com, BestBuy.com or Walmart.com account (or all three).
• Make sure your payment and shipping info is up to date to save time later.
• Add the item(s) you want to buy to a new "wishlist" or "save for later" list.
• (This script operates on the assumption that the items are out of stock or not available. If they're available... then just buy them.)

Usage

• Set your computer's volume appropriately and make sure it is within earshot.
• Navigate to the saved items page:
  • Best Buy: https://www.bestbuy.com/site/customer/lists/manage/saveditems
  • Walmart: https://www.walmart.com/lists (then click on the correct list.)
  • Amazon: https://www.amazon.com/gp/registry/wishlist/ (then click on the correct list.)
• The script will run automatically on each of the above pages.
• You'll hear an annoying, repeating, audible alert when an item has been successfully added.
  • Head to your computer quickly and complete your purchase.

TODO

• Move the selectors into GM local storage to allow end users to customize settings instead of having to edit the script itself.
• Register a browser menu button to toggle the search/refresh on/off per-site.

add_to_cart.user.js

// ==UserScript==
// @name         Add Saved Items to Cart
// @namespace    https://gist.github.com/beporter/ce76204bcba35d9edb66b395bb5e9305
// @version      0.5
// @description  Repeatedly refresh a given "saved items" page (Amazon, Walmart, BestBuy), look for specific "Add to Cart" buttons, click them if present, and make a lot of noise on success.
// @author       https://github.com/beporter
// @match        https://www.amazon.com/gp/registry/wishlist/*
// @match        https://www.amazon.com/hz/wishlist/ls/*
// @match        https://www.bestbuy.com/cart
// @match        https://www.bestbuy.com/site/customer/lists/manage/saveditems
// @match        https://www.walmart.com/lists*
// @grant        none
// @run-at       document-idle
// @require      https://cdnjs.cloudflare.com/ajax/libs/howler/2.1.3/howler.min.js#sha256-/Q4ZPy6sMbk627wHxuaWSIXS1y7D2KnMhsm/+od7ptE=
// @downloadURL  https://gist.githubusercontent.com/beporter/ce76204bcba35d9edb66b395bb5e9305/raw/add_to_cart.user.js
// ==/UserScript==

(function() {
    'use strict';

    const SELECTORS = [
        {
            site: 'Walmart',
            urls: ['https://www.walmart.com/lists'],
            selector: 'div.ListDetails button.RegularItemTile-add-to-cart',
            loadWait: 2,
            cooldown: 5, // Set to 0 to disable the refresh.
            active: true,
        },
        {
            site: 'BestBuy',
            urls: ['https://www.bestbuy.com/site/customer/lists/manage/saveditems'],
            selector: '#your-saved-items .add-to-cart-button button:not([disabled])',
            loadWait: 5,
            cooldown: 5,
            active: true,
        },
        {
            site: 'Amazon',
            urls: ['https://www.amazon.com/gp/registry/wishlist/', 'https://www.amazon.com/hz/wishlist/ls/'],
            selector: 'div#my-lists-tab span[data-action=add-to-cart] a[role=button]',
            loadWait: 5,
            cooldown: 5,
            active: true,
        },
    ];

    var readySound = new window.Howl({
      src: ['//freesound.org/data/previews/187/187404_635158-lq.mp3'],
      autoplay: false,
      loop: true,
      volume: 1.0,
    });

    // Scan the page for the provided selector and "click" them if present.
    function triggerClicks(sel) {
        var anyClicked = false;
        const buttons = document.querySelectorAll(sel.selector);

        // No available "Add to Cart" buttons. Cool down and refresh.
        if (!buttons.length) {
            console.log(`${sel.site}: No active "Add to Cart" buttons.`);
            return anyClicked;
        }

        buttons.forEach((b) => {
            var clickEvent = document.createEvent('MouseEvents');
            clickEvent.initEvent('click', true, true);
            b.dispatchEvent(clickEvent);
            console.log(`${sel.site}: Clicked "Add to Cart" button.`);
            anyClicked = true;
        });

        return anyClicked;
    }

    function refreshInSecs(secs) {
        console.log(`Scheduling page refresh in ${secs} secs.`);
        window.setTimeout(() => {
            window.location.reload(true);
        }, secs * 1000);
    }

    function waitToClick(sel, callback) {
        console.log(`Scheduling clicks for ${sel.site}.`);
        window.setTimeout(() => {
            callback(sel);
        }, sel.loadWait * 1000);
    }

    function locationStartsWithAnyOfUrls(urls) {
        return urls.reduce((acc, url) => {
            return acc || window.location.href.startsWith(url);
        }, false);
    }

    // function main()
    SELECTORS.forEach((sel) => {
        if (sel.active && locationStartsWithAnyOfUrls(sel.urls)) {
            waitToClick(sel, (sel) => {
                if (triggerClicks(sel)) {
                    readySound.play();
                } else if (sel.cooldown) {
                    refreshInSecs(sel.cooldown);
                }
            });
        }
    });

})();

Would this be possible to get in touch to see about using this script on another site where an item is out of stock but then is loaded in and it automatically puts it to final checkout screen?