From d1d654ebac2d51e3841675faeb56480e440f622f Mon Sep 17 00:00:00 2001
From: Wolfgang Müller
Date: Tue, 5 Mar 2024 18:08:09 +0100
Subject: Initial commit

---
 frontend/src/lib/Actions.ts | 109 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 frontend/src/lib/Actions.ts

(limited to 'frontend/src/lib/Actions.ts')

diff --git a/frontend/src/lib/Actions.ts b/frontend/src/lib/Actions.ts
new file mode 100644
index 0000000..7231c2f
--- /dev/null
+++ b/frontend/src/lib/Actions.ts
@@ -0,0 +1,109 @@
+export function debounce(
+	node: HTMLInputElement,
+	{ callback, timeout = 500 }: { callback: () => void; timeout?: number }
+) {
+	let timer: NodeJS.Timeout;
+
+	function trigger(event: KeyboardEvent) {
+		clearTimeout(timer);
+		if (event.key !== 'Enter') {
+			timer = setTimeout(callback, timeout);
+		} else {
+			callback();
+		}
+	}
+
+	node.addEventListener('keyup', trigger);
+
+	return {
+		destroy() {
+			clearTimeout(timer);
+			node.removeEventListener('keyup', trigger);
+		}
+	};
+}
+
+export function clickOutside(
+	node: HTMLElement,
+	{ handler, ignore }: { handler: () => void; ignore?: HTMLElement }
+) {
+	const handle = (event: Event) => {
+		const target = event.target as HTMLElement;
+		if (!target || target === ignore) return;
+
+		if (node && !node.contains(target) && !event.defaultPrevented) {
+			handler();
+		}
+	};
+
+	document.addEventListener('click', handle, true);
+
+	return {
+		destroy() {
+			document.removeEventListener('click', handle, true);
+		}
+	};
+}
+
+export const focusableElements = [
+	'a[href]',
+	'area[href]',
+	'input:not([disabled]):not([type="hidden"]):not([aria-hidden])',
+	'select:not([disabled]):not([aria-hidden])',
+	'textarea:not([disabled]):not([aria-hidden])',
+	'button:not([disabled]):not([aria-hidden])',
+	'iframe',
+	'object',
+	'embed',
+	'[contenteditable]',
+	'[tabindex]:not([tabindex^="-"])'
+];
+
+let trapped: HTMLElement[] = [];
+
+export function trapFocus(node: HTMLElement) {
+	function handler(event: KeyboardEvent) {
+		if (event.target === window) return;
+
+		// return if we're not the topmost node to handle
+		if (trapped.at(0) !== node) return;
+
+		const focusable = node.querySelectorAll<HTMLElement>(focusableElements.join());
+
+		const first = focusable[0];
+		const last = focusable[focusable.length - 1];
+
+		if (event.key === 'Tab') {
+			if (!node.contains(document.activeElement)) {
+				first.focus();
+				event.preventDefault();
+			}
+
+			if (event.shiftKey && event.target === first) {
+				last.focus();
+				event.preventDefault();
+			} else if (!event.shiftKey && event.target === last) {
+				first.focus();
+				event.preventDefault();
+			}
+		}
+	}
+
+	if (document.activeElement instanceof HTMLElement) {
+		// if we trap focus, make sure to blur any previously selected external
+		// item such that focus does not remain outside of the node
+		if (!node.contains(document.activeElement)) {
+			document.activeElement.blur();
+		}
+	}
+
+	document.addEventListener('keydown', handler);
+	trapped.unshift(node);
+
+	return {
+		destroy() {
+			document.removeEventListener('keydown', handler);
+			trapped = trapped.filter((i) => i !== node);
+		}
+	};
+}
-- 
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