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html/static/js/modules/SubscribeButton.js

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+import {ElemJS} from "/static/js/elemjs/elemjs.js"
+
+class SubscribeButton extends ElemJS {
+	constructor(element) {
+		super(element)
+		this.subscribed = this.element.getAttribute("data-subscribed") === "1"
+		this.ucid = this.element.getAttribute("data-ucid")
+		this.on("click", this.onClick.bind(this))
+		this.render()
+	}
+
+	onClick(event) {
+		event.preventDefault()
+		this.subscribed = !this.subscribed
+		const path = this.subscribed ? "subscribe" : "unsubscribe"
+		fetch(`/formapi/${path}/${this.ucid}`, {method: "POST"})
+		this.render()
+	}
+
+	render() {
+		if (!this.subscribed) this.text("Subscribe")
+		else this.text("Unsubscribe")
+	}
+}
+
+export {
+	SubscribeButton
+}