LRUCache

LRUCache-class.js

class LRUCache {
	constructor(size) {
		this.size = size;
		this.cache = new Map();
	}

	put(key, value) {
		const { cache, size } = this;
		if(cache.has(key)) {
			cache.delete(key);
		} else if(cache.size >= size) {
			cache.delete(cache.keys().next().value);
		}
		cache.set(key, value);
	}

	get(key) {
		const { cache } = this;
		if(cache.has(key)) {
			const value = cache.get(key);
			cache.delete(key);
			cache.set(key, value);
			return value;
		}
		return -1;
	}
}

LRUCache-prototype.js

function LRUCache(size) {
	this.size = size;
	this.cache = new Map();
}

LRUCache.prototype.put = function(key, value) {
	const { cache, size } = this;
	if(cache.has(key)) {
		cache.delete(key);
	} else if(cache.size >= size) {
		cache.delete(cache.keys().next().value);
	}
	cache.set(key, value);
};

LRUCache.prototype.get = function(key) {
	const { cache } = this;
	if(cache.has(key)) {
		const value = cache.get(key);
		cache.delete(key);
		cache.set(key, value);
		return value;
	}
	return -1;
}