export function first(map) {
	console.assert(map instanceof Map, map);

	return map.entries().next().value;
}



export function getOrCreate(map, key, createCallback) {
	console.assert(typeof map === "Map", map);
	console.assert(typeof createCallback === "function", createCallback);

	if (!map.has(key))
		map.set(createCallback(map, key));
	return map.get(key);
}



export function last(map) {
	console.assert(map instanceof Map, map);

	let result = undefined;
	for (let entry of map.entries())
		result = entry;
	return result;
}



export function take(map, key) {
	console.assert(map instanceof Map, map);

	let value = map.get(key);
	map.delete(key);
	return value;
}