rg download button

rg-download-button.js

// ==UserScript==
// @name         RG Download Button
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Add download button
// @author       Vasileios Pasialiokis
// @match        https://www.redgifs.com/*
// @icon         data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
// @grant        none
// ==/UserScript==
(function() {
	const empty = x => x.innerHTML = ''

	const throttled = (f, t) => {
		let id = null

		function run() {
			id = null
			f()
		}

		return () => {
			if (id) return
			f()
			id = setTimeout(run, t)
		}
	}

	function E(tagname, props, children) {
		const e = document.createElement(tagname)
		if (props)
			for (const k in props)
				e[k] = props[k]
		if (children)
			for (const x of children)
				if (typeof x === 'string')
					e.appendChild(document.createTextNode(x))
				else
					e.appendChild(x)
		return e
	}

	const anchors = x => x.children[0].tagName === 'A'

	function on_mutation() {
		const last_items = document.querySelectorAll('.SideBarWrap > ul > li:last-child')
		for (const x of last_items) {
			if (anchors(x)) continue
			empty(x)
			x.appendChild(make_anchor(x))
			x.style.paddingTop = '2rem'
		}
	}

	function make_anchor(elem) {
		return E('a', {
			href: elem.parentElement.parentElement.parentElement.querySelector('video').src,
			style: 'font-size: 2rem;',
			target: '_blank',
		}, [ '⬇️' ])
	}

	new MutationObserver(throttled(on_mutation, 500))
		.observe(document.body, { subtree: true, childList: true })

})()

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