declare namespace QuickLRU {
	interface Options<KeyType, ValueType> {
		/**
		The maximum number of items before evicting the least recently used items.
		*/
		readonly maxSize: number;

		/**
		Called right before an item is evicted from the cache.

		Useful for side effects or for items like object URLs that need explicit cleanup (`revokeObjectURL`).
		*/
		onEviction?: (key: KeyType, value: ValueType) => void;
	}
}

declare class QuickLRU<KeyType, ValueType>
	implements Iterable<[KeyType, ValueType]> {
	/**
	The stored item count.
	*/
	readonly size: number;

	/**
	Simple ["Least Recently Used" (LRU) cache](https://en.m.wikipedia.org/wiki/Cache_replacement_policies#Least_Recently_Used_.28LRU.29).

	The instance is [`iterable`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Iteration_protocols) so you can use it directly in a [`for…of`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Statements/for...of) loop.

	@example
	```
	import QuickLRU = require('quick-lru');

	const lru = new QuickLRU({maxSize: 1000});

	lru.set('🦄', '🌈');

	lru.has('🦄');
	//=> true

	lru.get('🦄');
	//=> '🌈'
	```
	*/
	constructor(options: QuickLRU.Options<KeyType, ValueType>);

	[Symbol.iterator](): IterableIterator<[KeyType, ValueType]>;

	/**
	Set an item.

	@returns The list instance.
	*/
	set(key: KeyType, value: ValueType): this;

	/**
	Get an item.

	@returns The stored item or `undefined`.
	*/
	get(key: KeyType): ValueType | undefined;

	/**
	Check if an item exists.
	*/
	has(key: KeyType): boolean;

	/**
	Get an item without marking it as recently used.

	@returns The stored item or `undefined`.
	*/
	peek(key: KeyType): ValueType | undefined;

	/**
	Delete an item.

	@returns `true` if the item is removed or `false` if the item doesn't exist.
	*/
	delete(key: KeyType): boolean;

	/**
	Delete all items.
	*/
	clear(): void;

	/**
	Iterable for all the keys.
	*/
	keys(): IterableIterator<KeyType>;

	/**
	Iterable for all the values.
	*/
	values(): IterableIterator<ValueType>;
}

export = QuickLRU;