Method put

javascript/0146-lru-cache.js:33–43

(key, value)

    }

    put(key, value) {
        const hasKey = this.get(key) !== -1;
        const isAtCapacity = this.map.size === this.capacity;

        if (hasKey) return (this.tail.prev.value = value);
        if (isAtCapacity) this.removeLastUsed();

        const node = { key, value };
        this.map.set(key, node);
        this.moveToFront(node);
    }

    moveToFront(node) {
        const [prev, next] = [this.tail.prev, this.tail];