Add hotkeys to Letterboxd's film detail page, like W for toggle watchlist

letterboxd-film-hotkeys.user.js

// ==UserScript==
// @name         Letterboxd Search Hotkey
// @namespace    hjdarnel
// @version      0.0.3
// @description  Press / anywhere on Letterboxd to search, W to toggle watchlist status
// @author       Henry Darnell https://github.com/hjdarnel
// @match        https://letterboxd.com/film/*
// @downloadURL  https://gist.github.com/hjdarnel/a4d5f24dc7917dc85a407a24386c99b1/raw/letterboxd-film-hotkeys.user.js
// @updateURL    https://gist.github.com/hjdarnel/a4d5f24dc7917dc85a407a24386c99b1/raw/letterboxd-film-hotkeys.user.js
// @icon         data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
// @grant        none
// ==/UserScript==

'use strict';

const sleep = (ms) => new Promise(res => setTimeout(res, ms));

document.addEventListener('keyup', async (event) => {
    switch (event.code) {
        case 'KeyW': {
            const removeEl = document.querySelector('a.remove-from-watchlist');
            const addEl = document.querySelector('a.add-to-watchlist');

            if (removeEl && !removeEl.parentElement.classList.contains('hidden')) {
                removeEl.click()
            } else if (addEl && !addEl.parentElement.classList.contains('hidden')) {
                addEl.click()
            }
            break;
        }
    };
})