Add "mark watched" button to subscriptions page

html/static/js/mark-watched.js

@@ -0,0 +1,24 @@
+import {ElemJS} from "/static/js/elemjs/elemjs.js"
+
+class MarkWatchedButton extends ElemJS {
+	constructor(element) {
+		super(element)
+		this.on("click", this.onClick.bind(this))
+	}
+
+	onClick(event) {
+		event.preventDefault()
+		let video = this.element
+		while (!video.classList.contains("subscriptions-video")) {
+			video = video.parentElement
+		}
+		video.classList.add("video-list-item--watched")
+		const form = this.element.parentElement
+		fetch(form.getAttribute("action"), {method: "POST"})
+		form.remove()
+	}
+}
+
+export {
+	MarkWatchedButton
+}

html/static/js/subscriptions.js

@@ -0,0 +1,6 @@
+import {qa} from "/static/js/elemjs/elemjs.js"
+import {MarkWatchedButton} from "/static/js/mark-watched.js"
+
+for (const button of qa(".mark-watched__button")) {
+	new MarkWatchedButton(button)
+}