rhl-lieferscheine/lib/frontend/ui/clipboard.js

function canUseClipboardApi() {
	return (
		typeof navigator !== "undefined" &&
		Boolean(navigator.clipboard) &&
		typeof navigator.clipboard.writeText === "function"
	);
}

function copyWithExecCommand(text) {
	if (typeof document === "undefined") return false;
	if (typeof document.execCommand !== "function") return false;

	const textarea = document.createElement("textarea");
	textarea.value = String(text ?? "");
	textarea.setAttribute("readonly", "");
	textarea.style.position = "fixed";
	textarea.style.top = "-9999px";
	textarea.style.left = "-9999px";
	textarea.style.opacity = "0";

	document.body.appendChild(textarea);
	textarea.focus();
	textarea.select();
	textarea.setSelectionRange(0, textarea.value.length);

	let copied = false;
	try {
		copied = document.execCommand("copy");
	} catch {
		copied = false;
	} finally {
		textarea.remove();
	}

	return Boolean(copied);
}

export async function writeTextToClipboard(text) {
	const value = String(text ?? "");

	if (canUseClipboardApi()) {
		try {
			await navigator.clipboard.writeText(value);
			return { ok: true, method: "clipboard" };
		} catch {
			// Fall back to execCommand below.
		}
	}

	if (copyWithExecCommand(value)) {
		return { ok: true, method: "execCommand" };
	}

	return { ok: false, method: null };
}