Subscribe & Save Canceller Userscript

subscribe-and-save-canceller.user.js

// ==UserScript==
// @name         Amazon Subscribe & Save Canceller
// @namespace    http://tampermonkey.net/
// @version      1.0
// @description  Add a button to cancel all Amazon Subscribe & Save subscriptions
// @author       -
// @match        https://www.amazon.com/auto-deliveries/*
// @grant        none
// ==/UserScript==

(function () {
    'use strict';

    function addCancelButton() {
        const button = document.createElement('button');
        button.textContent = 'Cancel All Subscriptions';
        button.style.position = 'fixed';
        button.style.top = '10px';
        button.style.right = '10px';
        button.style.zIndex = '10000';
        button.style.padding = '10px';
        button.style.backgroundColor = '#d00';
        button.style.color = 'white';
        button.style.border = 'none';
        button.style.borderRadius = '5px';
        button.style.cursor = 'pointer';

        button.addEventListener('click', async () => {
            const subscriptionElements = [...document.querySelectorAll('[data-subscription-id]')];

            await Promise.all(subscriptionElements.map(el => el.getAttribute('data-subscription-id')).map(async (subscriptionId) => {
                try {
                    const res = await fetch(`https://www.amazon.com/auto-deliveries/ajax/cancelSubscription?deviceType=desktop&deviceContext=web&subscriptionId=${subscriptionId}`);
                    const cancelPanel = await res.text();

                    const div = document.createElement('div');
                    div.innerHTML = cancelPanel;
                    document.body.appendChild(div);

                    const form = div.querySelector("form[name='cancelForm']");
                    if (form) {
                        const formData = new FormData(form);
                        const formEntries = Object.fromEntries(formData.entries());

                        await fetch(form.action, {
                            method: form.method,
                            headers: {
                                'Content-Type': 'application/x-www-form-urlencoded',
                            },
                            body: new URLSearchParams(formEntries)
                        });
                    }

                    div.remove();
                } catch (e) {
                    console.error(`Error cancelling subscription ${subscriptionId}:`, e);
                }
            }));

            alert('Done processing all subscriptions.');
        });

        document.body.appendChild(button);
    }

    window.addEventListener('load', addCancelButton);
})();