extensions/image-preview/src/preview.ts/getNonce
function getNonce() {
	let text = '';
	const possible = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
	for (let i = 0; i < 64; i++) {
		text += possible.charAt(Math.floor(Math.random() * possible.length));
	}
	return text;
}